We all know that RAM clock and timings are usually not super critical for gaming. (Exceptions mostly including IGP performance.) However, SC2 is much more CPU dependent than a lot of games, and that stuff has to go somewhere before your display. To satisfy my own curiosity, I've decided to bench some RAM clocks and timings, to see if it's worth paying a little more for low voltage memory to OC it and tighten timings.
Obviously, some of this will be CPU dependent due to recent processors having the memory controller on-die instead of using the motherboard, so don't take my results as gospel for your system.
Methodology: Replay of maxed supply vs maxed supply of Zerglings A-Moved towards each other on the Unit Tester custom map, using FRAPS to record framerates. All graphics
settings on low except CPU settings on Ultra and Models on high. 30 Second FRAPS bench run
with Start at the same time each test, following the replay camera.
Test Rig: i7 930 HT disabled, Turbo disabled. 6GB OCZ Reapers at listed clocks/timings
SLI GTX 460 @ 820Mhz
Memory timings to be tested: 9 9 9 30 and 6 9 6 30.
Not sure why OCZ suggests the 8 9 8 and 7 9 7, but they do, and I stuck with the
formula for CL6 and it still worked. Since 1333 CL9 is sort of "standard" for DDR3,
I'm going to call that framerate 100%, and performance for the others will also be
shown as percentage of that performance, for easier assessment.
FPS Shown in Min/Max/Average
2.8Ghz CPU Clock
1066 CL9 FPS: 28/133/61.6--95%
1066 CL6 FPS: 28/134/62.6--96.6%
1333 CL9 FPS: 30/139/64.8--100%
1333 CL6 FPS: 30/139/65.2--100.6%
1600 CL9 FPS: 31/142/67.2--103.7%
1600 CL6 FPS: 31/142/67.3--103.8%
For giggles, the same test with my normal OC @3.8Ghz w/ 3600 Uncore.
1600 CL6 FPS: 50/193/95.1--146.7%
If anyone wants to make a pretty graph of this after I finish getting results, I'll happily add it with credit to the artist. I'm terrible at that sort of stuff.
Conclusion: SC2 pretty much couldn't care less what your timings are. Clock speed, on the other hand, makes a few percent difference in the thick of the action, and those couple of frames minimum can be a big difference when they're fairly low like the high supply situations. Minimum framerate can be what really counts, since that's where you suffer the most, and in the thick of the fight, the average definitely seems to benefit from faster RAM.
Since DDR3 1333 CL9 tends to run ~$8 US/GB (for the rationally priced stuff), I'd say if you can keep it to ~$10 US/GB to get some low voltage RAM, or better binned memory tested at 1600Mhz, it might be worth the step up.
Aside from that, you're still looking better off with a healthy overclock on your CPU than you are with faster memory. If you're looking at any more than a few dollars premium, you'd do better to spend the money on a faster CPU, or a better mobo and cooler to OC with.
Obviously, this is for the people who care about price/performance in the slightest. If you happen to have a license for 3DMark, if your desktop has more benchmark utilities than games, obviously you don't care much anyways, because you'll get something, anything, out of it. So it's worth it. But if you can only raise the clock or tighten the timings, but not both... for SC2, at least, the answer is clear.