Hi gerbils. I was playing around with my PC for the past few days trying to troubleshoot choppy gameplay. While I was at it I've realized that my PC was running slower when only 2 of the 4 DIMM slots were populated. This was also chronicled in my recent post about this problem (General Hardware > PC Becoming Slow). Since I believe this deserves a separate thread under RAM, here I am with this new thread.
My specs are as follows: AMD Phenom II X3 720 (unlocked to X4, no OC), MSI 785GM-E65, 4GB or 8GB of Apacer DDR3-1333, AMD HD4670 512MB, 1TB Hitachi HDD, 2 x LG ODDs, ACBel 600+W PSU.
I'm using Passmark (Memory Mark) to test the RAM's performance. When only 2 DIMMs are filled, I get a score of around 800 (Dual Channel mode, as reported by CPU-Z and also following the manual's recommendation for Dual Channel operation). With all 4 DIMM slots filled, the score jumps to about 1,200. I'd hate to think that memory performance is actually lower with fewer DIMMs installed.
I also tested 2 x 4GB DDR3-1333 (instead of 2 x 2GB DDR3-1333) from another PC and I still got low scores of ~800 in Passmark.
NEC V20 > AMD Am386DX-40 > AMD Am486DX2-66 > Intel Pentium-200 > Cyrix 6x86MX-PR233 > AMD K6-2/450 > AMD Athlon 800 > Intel Pentium 4 2.8C > AMD Athlon 64 X2 4800 > AMD Phenom II X3 720 > AMD FX-8350