RAM not working at full clock speed

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Stilgar wrote: I just registered to ask about precisely the same problem so I guess I will just use this thread. I got ASRock Z170 Extreme 4 i5 6600K HyperX HX432C16PB3K2/16 (2x8GB DDR4 3200). Both CPU-Z and UEFI say the memory is running as DDR4-2400 (1200Mhz). Tried to force it to run as 3200 through the overclocking menu and via the XMP profile but just ended up with boot guard telling me several boot attempts were unsuccessful and reverting to DDR4-2400. This memory is not in the list of supported memory ( http://www.asrock.com/mb/Intel/Z170%20Extreme4/index.us.asp?cat=Memory&Model=Z170 Extreme4&Vendor=HyperX ). Also update the BIOS to the latest version (3.40 I think) but the problem still persists. Thanks in advance for any help.

May be a compatibility issue.

Of the 30 HyperX Modules/Kits Kingston lists, they only state compatibility of up to 2666 memory compatible for/with your Z170 Extreme4.

http://www.kingston.com/us/memory/search?DeviceType=7&Mfr=ASR&Line=Motherboard&Model=93033

You should contact Kingston and inquire of compatibility of the specific kit you have.

http://www.hyperxgaming.com/us/support/technical/products?model=memory



Edited to include HyperX compatible modules/kits


Edited by wardog - 27 Aug 2016 at 12:14pm

Stilgar wrote: @wardog thanks. It seems like I should be more careful when choosing RAM. The support page requires a revision number and I don't know where to find that. I will look into it again. In other news it seems like I was doing overclocking wrong. My overclock settings weren't applied. Seems like the reason was I didn't create a profile. When I did I was able to increase the RAM frequency but only to DDR4-2800 as 3000 fails to boot. I also tried to apply the XMP profile timings. I really hope that 15-17-17-36 in the XMP Profile 2 means that I can set the CAS Latency to 15, RAS to CAS Delay and Row Percentage (tRCDtRDP) to 17 and RAS Active Time (tRAS) to 36 while the RAM is running as DDR4-2800. I did a 2 hour test with IntelBurn Test stress tool and played the new DooM for a couple of hours with no issues so it gives me some confidence that I am doing things right. I think I can just wait and hope for a bios update that adds support for this memory.

Skylake 'K' processors are guaranteed by Intel to work with DDR4 memory at speeds up to 2133. Any memory speed above that is an over clock, and not guaranteed.

http://ark.intel.com/products/88191/Intel-Core-i5-6600K-Processor-6M-Cache-up-to-3_90-GHz#@specifications

The quality of the memory controller in your CPU, the quality of the connections between the DIMM slots and the CPU socket, and the quality of the DDR4 memory are all variables in the memory over clock lottery. None of those things are affected by a BIOS update.

The two current Intel platforms that support DDR4 memory, X99 and Skylake, have differing requirements regarding memory parameters, such as VCCIO and VCCSA voltages, among others.

That means the XMP profile for DDR4 used in X99 systems is not 100% compatible with Skylake systems. Memory manufactures don't like dealing with that, or having separate memory models for both platforms.

I have both systems, and have yet to see an XMP profile that works perfectly on either of them. Of course I have not used that many models of memory, so I cannot say that is true of all DDR4 memory. I have learned that XMP profiles are similar to built in/automatic CPU over clocking profiles in the UEFI/BIOS, regarding the VCCIO and VCCSA voltages. Their values are set much higher than necessary for some processors, but again they are dealing with variables and chance.

What are the values for VCCIO and VCCSA voltages when you use the 3200 XMP profile?