What quantity of memory should you install in your Core i7 system?

Once we had settled on the Asus P6T SE motherboard with OCZ Reaper memory we carried out a final simple test. We benchmarked the system with 12GB of triple-channel memory and then reduced the amount of memory for subsequent tests.

PCMark Vantage Results

Longer bars are better

SiSoft Sandra Results
Bandwidth

Memory Bandwidth in Gigabytes per Second (GB/s)
Longer bars are better

Latency

Memory Latency in Nanoseconds (ns)
Shorter bars are better

The next step was 6GB in triple-channel mode, followed by 4GB of dual-channel memory and, finally, we tested with 4GB of single-channel memory. The winning set-up was 12GB of memory in triple-channel mode but it occurred to us that suspicion may be hanging over PCMark Vantage. We ran a final benchmark with Far Cry 2 and found that the 12GB and 6GB triple-channel systems had a modest advantage over the 4GB dual- and single-channel systems.

Far Cry 2 Results

Frames per Second (f/s)
Longer bars are better

Verdict
Stuff your 64-bit Core i7 system with 12GB of memory and you’ll reap the benefits.

Final Verdict

So there we have it: the Core i7's triple-channel memory controller shows little benefit over dual-channel but it doesn’t do any actual harm. Running astronomical memory speeds on Core i7 is a bit of a lost cause, and we recommend you stick to a maximum speed of 1333MHz, although the default 1066MHz speed works very nicely too. 12GB of memory works well but you’ll need a 64-bit operating system, and that's the real conclusion that we are taking away from all these days of testing. Don’t build a new Core i7 PC and run 32-bit software, but instead make the jump to 64-bit and pack it full of Ram. ®

More Hands On

• Group Test Intel P55-based motherboards (12 November 2009)
• Inside USB 3.0 (25 May 2009)
• Zen and the Art of Laptop Battery Maintenance (7 May 2009)
• G.hn-ing for gigabit (27 February 2009)
• MSI mobo ditches Bios for EFI (23 December 2008)