And this is basically a limitation of how CPU utilization is measured. Yes, a RAM-bottleneck will be reported as "CPU Utilization" on both Windows and Linux. In both cases of CPU-bound and RAM-bound code, Windows will report 100% "CPU Utilization" on the threads, which makes it confusing for some people. In the case of video games or databases, the vast majority of the time the CPU is just sitting around waiting for RAM to respond. Simple Photoshop filters (blur) are processed very quickly by the CPU, so the CPU runs out of work to do and ends up waiting for RAM IIRC. Some problems are strongly RAM-bandwidth bound instead. This is NOT the case with video games, or other benchmarks. As long as the CPU has work to do in its on-board memory (Registers, L1, L2, or 元 cache), the CPU will operate in parallel with RAM. Note: Modern CPUs execute "in parallel" with RAM. Needless to say, many macroblocks can fit in L1 cache, so the CPU has plenty of work to do while waiting for RAM to respond. Yeah, you only need one AVX512 register to fit a 8-bit 8x8 pixel Macroblock. In particular: video encoders are set up to operate on Macroblocks (which fit in a few SIMD Registers !!). That's because video-encoders are designed to operate mostly out of cache, probably L1 or L2 cache for most of their calculations. Thanks! That article was very helpful! It looks like a few games had FPS increases, but not much.Īnd this statement from the conclusion seems notable: "It came as a bit of surprise to us that memory speed didn't even affect performance of CPU-intensive tests, such as video-encoding in which large data streams are being pushed in and out of the main memory." Even for games, it appears to be very dependent on the specific game. OK, so it looks like going from 2666 to 3200 on the RAM has negligible effects on these types of workloads. Thanks.Ĭheck out TPU's render benchmark scaling: I'm curious if anything has any thoughts or insights. From what I had read about the Ryzen, I thought overclocking the RAM would increase overall performance by at least a single-digit percent.Ĭould 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. Therefore, I found it very interesting that overclocking my RAM from stock 2666 MHz up to 2933 or 3200 had no effect on performance. But since no errors occurred in the time-frame in question, we know that errors weren't reducing performance. So there's no guarantee that these settings were stable. I did not stress-test these RAM settings to see if errors would have eventually occurred. 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. 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). OC #2: 3200 MHz, CL 20, tRCD 22, tRP 22, tRAS 52, tRC 74, CR 1Tīlender Blenchmark: forgot to run at this settingĬinebench R15: 175 single-thread, 1785 multi-thread Surprisingly, higher RAM clocks had no effect on performance.ĭefault: 2666 MHz, CL 19, tRCD 19, tRP 19, tRAS 43, tRC 62, CR 1TĬinebench R15: 175 single-thread, 1774 multi-thread So as a first pass, I used my motherboard's automatic overclock ("EZOT") to overclock the RAM for me. My understanding is that Ryzen greatly benefits from higher RAM clock speeds, even if the timings have to be much looser. RAM: 2x16 GB Kingston KSM26ES8/8ME (DDR4 2666 MHz ECC CL19 single-rank Micron E) I thought this was odd, so I wanted to see how others reacted. I just successfully overclocked my RAM on a new Ryzen system, but it had no effect on performance.
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