topic Re: 750 PCIe not recognized when memory is set to 3000 MHz in Solid State Drives (NAND)

750 PCIe not recognized when memory is set to 3000 MHz

AVeik — Wed, 16 Sep 2015 15:09:10 GMT

Motherboard: Evga z170 classified

CPU: i7-6700k

Memory: G.Skill F4-3000C15Q-16GRK (4x4GB DDR4-3000)

Boot SSD: Samsung 850 Pro

SSD: 750 PCIe 1.2TB

GPU: Asus GTX 980 STRIX

I have noticed that when I set my memory to 3000 Mhz in the bios this SSD doesn't initialize. The bios acts as if nothing is in the slot it's in. I've tried different slots as well.

Other than that my system is stable. Ran a stress test overnight with no issues.

CPU is running stock. I'm technically overclocking the memory controller with this ram though. Is this just a limitation of the integrated memory/io controller or is there something else I'm missing?

Re: 750 PCIe not recognized when memory is set to 3000 MHz

AP16 — Wed, 16 Sep 2015 16:55:56 GMT

The DRAM frequency is linked to CPU BCLK frequency, although 170 chipset should be capable to DRAM frequencies up to 3200 MHz with standard BCLK clock of 100 MHz, MB BIOS may change BCLK frequency earlier. BCLK frequency determine PCIE frequency (for lanes from CPU), so if it became more that standard, the PCIE clock will also be greater, so your SSD lost. Check the MB manual for details about frequency dependencies, also try to find a BCLK Frequency : DRAM Frequency Ratio option in BIOS setup.

Re: 750 PCIe not recognized when memory is set to 3000 MHz

AVeik — Wed, 16 Sep 2015 17:34:28 GMT

Thanks I'll look into this when I get home.

I know I left the BCLK at 100. The SSD is in slot 5 which is an x4 slot fed from the PCH. Does the PCH use BCLK as well?

I don't recall seeing a DRAM ratio option. I'll look around and see if I overlooked it.

Re: 750 PCIe not recognized when memory is set to 3000 MHz

AP16 — Thu, 17 Sep 2015 12:20:36 GMT

Did a look into chipset datasheet, according to scheme on p.175 of http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/100-series-chipset-datasheet-vol-1.pdf http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/100-series-chipset-datasheet-vol-1.pdf CPU BCLK and PCIE base clocks comes from same PLL in PCH, so all PCIE slots are in one boat.

Re: 750 PCIe not recognized when memory is set to 3000 MHz

AVeik — Thu, 17 Sep 2015 14:05:36 GMT

I verified if I changed the BCLK and keep the memory under 3000MHz it duplicates the issue. I didn't see any other ratio's though in the bios. Working with eVGA support right now to determine what's going on.