Why Does CPU-Z Indicate DRAM Is Only Running At X Speed?
The answer to this question depends on what you are looking at in CPU-Z. Two of the program's tabs are DRAM-related: the SPD tab and the Memory tab. We will get to the SPD tab in Item No. 10 below, but this question most often arises in the Memory tab of the program.
CPU-Z shows DRAM clock rate and timings, among other things, in the Memory tab. DRAM data rate is most often thought of as the DRAM’s "speed." Since this is DDR (double data rate) DRAM, the indicated frequency times two equals the data rate. If, for example, your DRAM is 1866 or better and you are seeing 667 (=1333) or 800 (=1600) or anything less than what equates to the spec of your DRAM (1866 should show ~933), then one of the following issues is occurring: your DRAM is not set up correctly, the motherboard or CPU isn't capable of running the specification data rate of the DRAM, or there is another problem.
An example is provided below:
The examples above show the DRAM after the initial installation. You can see that the Memory tab image is showing a true frequency of 668.9. Going back to our formula of frequency x 2 = effective data rate, 668.9 x 2 = 1337.8 (or basically 1333, the motherboard’s default).
In the SPD image, we see the XMP profile for 2400 MT/s DRAM. Asus uses DOCP in AMD rigs. These were described in item No. 5. DOCP-capable firmware doesn’t always read or report exact XMP timings. Here, they appear as DDR3-2400 with timings of 10-13-13-32 when its original XMP values are 10-12-12-31.
Once DOCP has been enabled, it sets the timings to 11-13-13-35 for 2400. After the timings were manually corrected, it showed the correct data rate of 2400 MT/s with the correctly entered timings.