Howdy y'all. I just successfully overclocked my RAM on a new Ryzen system, but it had no effect on performance. I thought this was odd, so I wanted to see how others reacted.
CPU: Ryzen 7 2700X
Motherboard: Gigabyte X470 Gaming 7 Wifi
RAM: 2x16 GB Kingston KSM26ES8/8ME (DDR4 2666 MHz ECC CL19 single-rank Micron E)
My understanding is that Ryzen greatly benefits from higher RAM clock speeds, even if the timings have to be much looser. So as a first pass, I used my motherboard's automatic overclock ("EZOT") to overclock the RAM for me. Surprisingly, higher RAM clocks had no effect on performance.
Default: 2666 MHz, CL 19, tRCD 19, tRP 19, tRAS 43, tRC 62, CR 1T
Blender Blenchmark: 1:30
Cinebench R15: 175 single-thread, 1774 multi-thread
Corona 1.3: 2:04; 3,890,870 rays/sec
x265 0.1.4: 38.56s (29.25 fps); 38.52s (29.29 fps); 38.53s (29.27 fps); 38.53s (29.27 fps)
OC #1: 2933 MHz, CL 20, tRCD 21, tRP 21, tRAS 47, tRC 68, CR 1T
Blender Blenchmark: 1:30
Cinebench R15: 175 single-thread, 1740 multi-thread
Corona 1.3: 2:04; 3,906,290 rays.sec
x265 0.1.4: 37.55s (30.04 fps); 37.67s (29.94 fps); 37.60s (30.00 fps); 37.68s (29.93 fps)
OC #2: 3200 MHz, CL 20, tRCD 22, tRP 22, tRAS 52, tRC 74, CR 1T
Blender Blenchmark: forgot to run at this setting
Cinebench R15: 175 single-thread, 1785 multi-thread
Corona 1.3: 2:02; 3,963,260 rays/sec
x265 0.1.4: 37.79s (29.85 fps); 37.75s (29.88 fps); 37.48s (30.10 fps); 37.52s (30.06 fps)
The reason for the failure to achieve higher performance is not that that the RAM experiencing errors (which had to be corrected by the ECC, incurring a performance penalty). Windows Event Viewer logged no errors. I know that ECC is working because when I run "cmd /k wmic memphysical get memoryerrorcorrection" the output is "MemoryErrorCorrection 6", which indicates multi-bit ECC.
I did not stress-test these RAM settings to see if errors would have eventually occurred. So there's no guarantee that these settings were stable. But since no errors occurred in the time-frame in question, we know that errors weren't reducing performance.
Therefore, I found it very interesting that overclocking my RAM from stock 2666 MHz up to 2933 or 3200 had no effect on performance. From what I had read about the Ryzen, I thought overclocking the RAM would increase overall performance by at least a single-digit percent.
Could it be that the timings are too loose? Still, the timings at higher clock speeds aren't so much looser than stock, and I'd be surprised if such small increases in timings could entirely negate the benefits of a boost in clock speed.
I'm curious if anything has any thoughts or insights. Thanks.