Intel has doubled the amount of memory that the P45 can support, with a new limit of 16GB compared to the 8GB addressed by P35, which sounds handy but it's hard to see that it will benefit many desktop PC builders. The speed of the memory that is supported by P45 is the same as P35 and tops out at DDR2-800 or DDR3-1066, but this is where things get interesting.
Those are the official Intel figures so we are relying on MSI and other vendors to add support for faster memory. MSI claims that its various P45 models will either support DDR2 at 1,200MHz or DDR3 at 2,000MHz and as the P45 Platinum has four DDR2 memory slots we thought we knew what we were getting.
Initially, however, we ran into some problems. The BIOS correctly identified that our Corsair Dominator memory was capable of running at 1,066MHz, but system performance was pathetic as the front side bus was running at 133MHz instead of 333MHz.
Raising the speed manually in the BIOS resulted in a system that refused to POST. After some back and forth it became clear that the Auto memory settings were trying to run our Corsair Dominator memory at 1,000MHz or more, however any speed above 800MHz would cause the system to freeze. Raising the front side bus to 1,333MHz was fine provided we kept the memory speed down to 800MHz, so it was clear to us that a BIOS update was required to unlock the proper memory speeds.
Thankfully, MSI did eventually supply us with a new BIOS - 10J to replace 10H. This new BIOS solved the problems we'd encountered and after the update was complete we were able to run the memory at a proper speed, even if it made no difference whatsoever to the test results. This didn't come as a surprise as we hadn't changed the front side bus but settled for raising the clock multiplier and 800MHz DDR memory doesn't present a restriction to a 333MHz front side bus.
As an aside, it's worth noting that updating an MSI BIOS is a pain in the neck as the BIOS doesn't have a flashing utility and you cannot force the Live Update software to load a file from your hard drive. You can't even use an old fashioned floppy as the BIOS file is 4MB in size, so the only practical course of action is to format a bootable USB key and then copy across the flashing utility and BIOS file.