[SOLVED] 1600 MHz showing 1333 MHz in BIOS

[Janzie]

Hello

My old trusty computer have 2 Kingston 4 GB memory modules. The first one is KHX1600C9D3/4G (https://www.kingston.com/datasheets/khx1600c9d3_4g.pdf). Bios tells me that it is running at the speed of 1600 MHz.

The second one is KHX1600C9D3K2/8GX (https://www.kingston.com/datasheets/khx1600c9d3k2_8gx.pdf) (I just bought the second module). I don't understand why BIOS tells me that it is running at the speed of 1333 MHz. It is almost identical to my old one.

My motherboard is Asus A78M-A and if I enable D.O.C.P (ASUS BIOS feature on AMD platforms that translate the XMP settings to a compatible AMD form) memory modules will work just fine at the 1600 MHz.

Why the first module seems to be faster that the second module regarding the BIOS?

Thank You

https://imgur.com/a/NG1NYp1

 

[lynx1021]

That is strange, I looked at the specs and seem to be identical except one was a kit of 2-4GB. Have you looked at them in CPUIZ? Oh just noticed, most boards recommend to use A2 and B2 to run in dual channel mode, check your manual..

 

[Desch_]

i also just had to switch to a2 and b2 (2nd and 4th ram slot) to get my dual channel running properly.

id also check the mhz in cpuid and speccy before messing with the hardware though. good luck!

 

[Janzie]

Thanks for help

I tried to use A2 and B2 instead of A1 and B1 but it didn't help.

I have read the BIOS manual but it is very limited (https://dlcdnets.asus.com/pub/ASUS/mb/SocketFM2/A78M-A/E8865_A78M-A.pdf).

It says "The default memory operation frequency is dependent on its Serial Presence Detect (SPD), which is the standard way of accessing information from a memory module. Under the default state, some memory modules for overclocking may operate at a lower frequency than the vendor-marked value. To operate at the vendor-marked or at a higher frequency, refer to section 2.5 Ai Tweaker menu for manual memory frequency adjustment.".

As I wrote the modules work fine at the 1600 MHz. I'm just wondering why the BIOS thinks the second module would run at the 1333 MHz by default.

I have also installed CPU-Z. Please find the screen captures below.

https://imgur.com/a/Lw86I1d

 

[Janzie]

Hi all

This case is solved!

I contacted Kingston and after a couple of emails I got the following response: "The issue you noticed is due to an older revision of the same product. The revision of the product you have is around 2 years older than the latest revisions of this product. Kingston added the JEDEC 1600MHz profile to the latest revisions only and also updated the datasheet. The earliest revisions do not have the JEDEC profile rather than the XMP profile only for 1600MHz".