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Intel Core i5 661 review



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Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • Intel Core i5 661
  • CPU Core i5 661 3.33GHz Clarkdale Core LGA1156 (3 Year Manufacturer Warranty)


Our Score:


The Intel Core i5 661 is the first CPU we've seen of a new series based on the new Intel Clarkdale design and for want of a better description it lies somewhere towards the top end of the bottom half of Intel's current CPU line-up. In other words, it's kind of 'mid-range'.

This dual-core CPU is built on Intel's new 32nm manufacturing process and incorporates a graphics chip on the package, though not on the same die (the graphics uses a 45nm process). Collectively these new chips will be available under the Core i5 6xx and Core i3 5xx numbering schemes.

The key difference between these two ranges is that the 600s have Turbo Boost while the 500s do not. Turbo Boost is the ability of the CPU to automatically overclock one or more of its cores dependent on workload. When enabled, the CPU will constantly try and work at its maximum speed which, if all cores are under load, will likely be its reference speed. However, if only some of the cores are under load, the unused ones are clocked back and the extra thermal headroom is used to overclock the remaining cores resulting in better performance.

Clarkdale also takes advantage of Simultaneous Multi-Threading (SMT), which is the ability for each core of the CPU to run two threads at the same time thus speeding up multi-threaded operations or multitasking. Essentially, the CPU appears to the operating system like it has twice as many cores as it does but in the background it's merely optimising the order in which it executes code so you end up with a performance improvement. However, the improvement doesn't rival that of two physical cores.

With regards the rest of Intel's range, the Clarkdale CPUs can be thought of as replacing the Core 2 series as the entry level of Intel's line-up, though Core 2 and various Pentium branded chips are likely to be available in shops for some time to come. This will leave the Lynnfield range (Core i7 8xx and Core i5 7xx) as the mid- to high-end and the Bloomfield (Core i7 9xx) series at the top. All these CPUs are based on Intel's current overarching microarchitecture, Nehalem. In case you were wondering, yes, this is all rather confusing so rather than list the myriad subtle differences between all these ranges, we've put them in a table, where we hope everything will become clear.

The key things to note are that Bloomfield CPUs require a different socket (LGA1366) and motherboard chipset to the rest of the range and as such are out on there own at the high-end where it costs £350+ just for the CPU and motherboard. The rest of the range fits in the LGA1156 socket so the Core i5 661 and other Clarkdale chips should work with existing P55 chipset based motherboards, though a firmware update might be needed. As such you could easily buy a Core i3 530 (£90), say, then upgrade to a Core i7 860 (£231) further down the line.


February 18, 2010, 9:41 am

The problem is the NON-OPTIONAL! integrated graphics in the dual cores raises the TDP to nearly that of a quad core! It cannot be disabled, it merely idles so if your looking for a serious machine its time to go quad with an i5-750 (2.66GHz - 3.2GHz Turbo) at about £155 in my opinion. Another £130 on an ATI 5770 gets you one hell of a gaming rig..

Or you can have a very nice ATI dual core Athlon II X2 245 (2.9GHz) based system with the CPU costing about £45 and with much more capable integrated graphics, you can also add the same graphics card to make quite a nice gaming rig..

To me this CPU is simply overpriced and comes with something I for one dont want in a CPU as expensive as this.

Also the supplier is mentioned as overclockers.co.uk - I will merely say, DO NOT TOUCH THEM WITH A BARGE POLE! You can get the same goods cheaper elsewhere with MUCH better service. If something you buy from them ever breaks God help you. Anybody I have ever spoken to thats ever had to return something says the same and will not buy from them again either. Just want to warn other TR users of my friends and family's experiences..


February 18, 2010, 2:31 pm

Just to balance out the overclockers bashing, I buoght a fullsystem and monitor from them nearly 2 and a half years ago now and have had nothing but perfect service. Delivery was swift, the PC has been phenomenal and I've only had 1 problem which was recified with some of the best customer service I have ever received. My PC was refusing to boot and luckily I lived close to them at the time, I popped it down to them, they diagnosed it as faulty ram, and replaced it and had it ready for me in less than 18 hours. The thing that really impressed me, this was done outside of the warranty period with no cost to me at all.

Its alrigth bashing a company because you know some people who have had bad service, but conversely there will always be people who have had good service, should we all not use Dell? Plenty of people have complained about them.

But yea, back to the CPU it seems a bit daft to me, think the money would be better spent on a standard chip and a GPU


February 18, 2010, 2:33 pm

@Xenos: I have heard a lot of horror stories about overclockers but personally I've never had an issue and I've bought from them for years. Also, they've had a bit of a reshuffle recently and we're assured that they're more focussed on customer service now. Obviously we only have their word on that but it's at least a start.

As for the CPU, you're pretty much spot on. However, if you look at the performance figures, it actually holds up surprisingly well, especially if you don't plan to overclock.


February 18, 2010, 4:06 pm

@xenos - I thought the integrated GPU was disabled if you put the CPU in a P55 board, since it is obviously not able to use it without the required video outputs? So the TDP would be lower (although I could only see the benefit of this in HTPCs, as they overclock like crazy anyway), but I do agree that the price of over £160 for a dual core is ridiculous, especially when you consider the lower pricing of the i5 750, since 4 physical cores are vastly superior to 2 physical and 2 hyperthreaded cores.


February 18, 2010, 4:12 pm

I just bought a new Vaio S laptop (VPCS11V5E) with a Core i5 540M CPU. The first thing that surprises me is how cool it runs! The P8600 Core 2 Due 2.4GHz CPU in my Vaio Z is as hot as the Sun when the machine is just idle!


February 18, 2010, 4:40 pm

I agree with xenos! The i5 661 should be at least £40 cheaper to be considered a viable alternative. The i5-750 is a no brainer at its current price of £140 and the icing on the cake is its ability to be overclocked easily to 4Ghz.

Check out the link to see the jump in performance going from a dual core to quad core:


Although they have tested only games, its a good indicator of level of performance as games are still struggling to utilise all that multicore CPU horsepower.

We are at a stage were quad cores should be considered the minimum mid-range CPU's.


February 18, 2010, 10:28 pm

@smc8788 - The integrated graphics is of no use as you rightly say, you can't use it because the P55 motherboard has no video outputs, however it still sits there idling away.. They really didn't think about it too much did they? Makes me kind of mad tbh, complete waste of power!

@Binnsy & Ed - If you bought a full system from them you paid too much. If you live near them, great but unfortunately most of us don't and dealing with them on the phone involves a long queue and staff who couldn't care less. They are of the opinion they have done you a favour by selling you something and one of them even tried to tell me that my blue screening graphics card was fine and that some of them are just like that. Unfortunately ones that are "like that" are faulty and need replacement, not shipping back to myself at a cost of £20 with a shitty letter telling me there's nothing wrong with it! They did the exact same thing to my father twice with some RAM that I tested in another PC which was so bad it made it crash on bootup..

There are so many other online retailers out there that you don't need to excuse them, simply go elsewhere. They absolutely do not give a crap! No amount of reshuffling is going to change the opinion of the owners of that company, they set it up bought a boat and F'd off!

@Binnsy - One other thing the RAM would have most likely had a lifetime (10 year) warranty so they weren't really going out of their way. I have heard stories they behave with customers that are local to them but if your in another county its just tough luck.. Consider yourself lucky!!

I've also just (like 10 minutes ago) returned some memory to Play, one menu then a person answered straight away, I have the RMA number and address to send the item to and they were extremely polite! Perfect.. No conversation about who knows more about computers or what constitutes faulty or how he once had this exact same problem but just put up with it..

Here's a list of online retailers I have used enough to warrant giving an honest opinion..

Outstanding service.. Lambda-Tek.com (lighting quick delivery and excellent service), Scan.com (these guys know what they are doing), John Lewis (very professional), Play (outsourced returns phone service but works well), Amazon (pretty straight forward), Dell (again outsourced usually but excellent and polite), Oyyy (they seem to make more mistakes than they should but always very proactive in sorting things, usually a couriers fault to be fair).

Average.. Dabs (good until recently cocked up several orders - bought 4 adsl routers and 4 cable routers arrived, they have listed the product wrong on their site but 1 week later haven't given me an RMA number - they must have sold thousands of these wrongly), Ebuyer (Sometimes poor - paid for next day delivery on a £500 order, all came next day apart from the case, they would only refund the difference in postage cost (£2) rather than the full postage amount), PC World (They will try and sell you crap but do get it done), Apple (More of an annoyance they only offer a 1 year standard warranty but service is otherwise generally excellent), CCL (Had a monitor with pixel check that still had dead pixels, bit of a nightmare as a specific person deals with this, otherwise good).

Poor.. Overclockers.co.uk (yeehaaw - yes that's right, cowboys!), my local 'Laptop Workshop' (Absolutely horrific service, the guy is a complete piece of work and won't support a computer that is 2 hours old, even when there's nobody else in the shop he won't even look at it.)

Take from that what you will!

@Caleb - Dual cores are still plenty fast, its just that Intel in it's horribly annoying way have made it pointless to buy a dual core because they want to shove their integrated graphics down your throat, its anti competitive, there should be models without the integrated GPU.. Also WHERE are the 32nm quad cores? They have held them back on purpose and may never actually release them, instead skipping to 'Sandy Bridge' with its new delayed release of 2011, specifically because AMD haven't fielded and are unlikely to field anything which constitutes a significant threat to Intel. The signs of Intel not playing nicely are all there, save yourself money and buy AMD if you don't need the highest end system and help them to get one up on Intel!!


February 18, 2010, 10:30 pm

Overclockers.co.uk did so much for online computer stores when they first emerged. They were the first to truly cater to the enthusiast and had great customer service. They seem to be victims of their own success though and I have to say they are a shadow of their former self. After they messed around a couple of my friends with the return of faulty goods I'd never touch them again. The worst bit is I recommended them and was left feeling a bit sheepish!


February 19, 2010, 12:42 am

"They were the first to truly cater to the enthusiast and had great customer service"

Pffft! "Special Reserve" was the original 'enthusiast' site in the UK. It was a shame when they went down the pan, but they were pretty untouchable from the mid-90's up until 2001/2002.

I actually used to get excited when their catalogue used to drop through the letter box with all the latest components and stuff.


February 19, 2010, 2:47 am

@xenos Well, I still feel that dual core had their time and its time to move on to triple or quad core processors. I agree about the Intel/AMD situation. I've had my eye on the i7 920 from day one and instead of falling in price its gone up. How about that!! We need more competition period!!


February 19, 2010, 8:02 am

@Caleb - For the high end absolutely!


February 19, 2010, 4:52 pm

@Xenos - I still feel I need to disagree, one thing I forgot to mention with the RAM is the replacement stuff is actually of a higher quality and a completley different brand. They also swapped all 4 sticks to this better RAM and not just the faulty one. They were also very quick to answer and helpful on the phone, willing to arrange for a courier to take the system back, it was me that suggested dropping it off which they again accomadated.

I also wouldn't say I spent over the odds for my system, it cost about £200 more than buying all the parts seperately would have, including the delivery. But that also included a factory overclock on the cpu from 2.4ghz to 3.2 along with the 1 year warranty. At the end of the day it proved to be worth going for as it saved me the hassle of having to diagnose it myself (it wasn't immediately apparent the RAM was the issue) and I had a nice overclock the day it arrived. For me £200 was well worth that along with the warranty and time saved not having to build it myself.

At the end of the day there will always be people who have crap service with any company, it doesn't mean there arent hundreds of satisfied people out there who just arent shouting about it.

The only thing I can say is that for my PC and monitor I dropped £1700 of my own cash, and I would have abosouletly no worries giving them that again for my next machine.


February 19, 2010, 6:13 pm

@Binnsy - Do you work for them? There are rumours they write fake reviews about themselves. Your fairly persistant and nobody else seems to want to stick up for them quite that much..

If not, (I was joking) like I said count yourself lucky! Just don't make the mistake of recommending them to your friends, ala PoisonJam and me too at one point. (NEVER recommend a company after 1 transaction!)


February 19, 2010, 9:40 pm

@Xenos - Lol, no I don't though I have been accused of it before :P (though I would say that even if I did wouldn't I so cant really prove my innocence) I've recommended them to a couple of people and so far no one has had any problems, one of my friends had a HDD fail actually but he sent it off and had a new one back a couple of days later and its been all good since then. I've recommended their systems to the odd people on some forums I'm on too and they seem perfectly happy with them so far.

At the end of the day I've been thoroughly impressed by them, so I like to stick up for them from time to time, compared to the rather epic 3 month wait I had with Rock to sort out my laptop issues (it went back, took ages, i bought my desktop as I needed one, the laptop came back broken, to which I said look I have a desktop, can I have a smaller one instead, even though its worth less, waited ages, they sent me the one I wanted, that didn't work, sent it back, and finally got one that worked) they have been fantastic. Admitted its not a huge benchmark to put them against :P But the whole thing of my repair not being impressive because the RAM would have a lifetime warranty has come up before and I still think it is, just because the RAM was under warranty didn't mean they had to diagnose and do the fitting / swapping for free!

Its more just to balance it out to be honest, there are always more horror stories for companies on the internet than success stories. Mainly because people want to voice their complaints, you never get people signing up to say hey thanks, it all works fine.


February 20, 2010, 12:02 am

Who are Rock? (lol)

I agree but you do hear it about companies that go the extra mile, it takes years of hard work to earn a good reputation in business and just a few minutes to destroy it..

This applies to everybody, there's no reason to defend a business that can do well if sometimes it also does shockingly badly, its all about the minimum standard that's allowed to exist within a company. Some are happy to employ anybody others would rather pay staff a bit more and ask for a higher standard of work.


February 20, 2010, 9:03 pm

Started reading the comments to see if other people thought this processor as pointless as I do but entered a world of OC bashing haha. Ive used them for years and found them very good. Only had to return 1 item and that was taken care of no problem. Biggest issue is cost of P&P to NI, its painful. Oh and I love play but any problems and ive found them to be a nightmare.

Anyway, this processor, bit daft


February 22, 2010, 5:02 pm

@Xenos & Binnsy

I have to agree with Xenos on this one: STAY AWAY FROM OVERCLOCKERS! (unless you're local and tall:))

I bought an ATI 5850 and a Netgear DMP-111 recently. The person I talked to on the phone withi two weeks of purchase was rude and incompetent. He did not accept the fact that the ATI had a desgn fault that made it unable to work with rigs that use an additional RAID card (it needs too much system ROM space), so basically to him the card was "incompatible" but not poorly designed. This is when in the same rig I can install a 8800GTX, a GT240 and an ATI 5770 (lathough not at the same time:)). The DMP-111 disconnects at least once every 24hours, it is widely documented on the net (only found out after purchase!), but he wouldn't accept it was faulty.

This was the most arrogant and incompetent support/customer person I ever talked to.

I gave up, took my Adaptec RAID card out of my rig and kept the 5850, I bought a Draytek Vigor 120 to replace the Netgear DM-111P, but this is the last time Overclocker sees my money (and I've used them quite a lot in the past). They ARE cowboys!

Otherwise I agree 100% with Xenos's list of reliable/unreliable retailers, I have used most of them, and my rating about their service is nearly identical. Regarding service/exchange/refunds, Play, Amazon, Kikatek, and Scan come on the top of the list. They will keep my business!

Note to TrustedReviews: it would be time to take Overclockers off your list of dealers, because you are not doing your readers a favor by sending them their way.

If you really do believe management has changed recently, please tell them to contact me and rectify (order#3525419), I will post here to update... but my attempt was made three weeks ago, so I doubt it will happen.

Lee Jackson

February 25, 2010, 2:15 am

I'm going to chime in (late) with the "avoid overclockers at all costs" brigade. I wont regale you with my tale of woe, suffice to say that it will be a cold day in hell before I deal with them again.

Oh and crap processor, agreed.

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