RVE, 5960X, 128GB 2800 - bandwidth low

[orcinus]

I'm running the RVE-5960X-8x16GB 2800 C16 config at any setup and in all situations on Win10 64 AIDA 64 Extreme 5.90.4200 reports about 21k GB/s of memory read bandwidth.

The tool correctly reports the system is indeed running at 15-15-15-35 2T 2800MHz at 127.3MHz, 1:22 multiplier, 4GHz NB Frequency, quad-channel as active. Full 128GB complement working.

BIOS I 3504. Memory is G.Skill 2800C16 (used timings from the XMP2). Voltage to Sys Agent is 1,168V, CPU voltage is 1,26V, but voltage or CPU did not make any diff. in performance.

Memory: G.SKILL Ripjaws 4 Series F4-2800C15Q2-128GRKD DDR4 2800 MHz 128 GB Memory Kit - Black
BIOS: 3504
CPU: i7-5960X
OS: Windows 10 x64 Enterprise, fully/regulary patched
AIDA64 Extreme 5.90.4200
Applied XMP2
System Agent Voltage tested: 1.162V-175V
CPU Voltage tested: 1.02V-1.3V
Memory voltage tested: 1.35V-1.4V
Timings tested: 15-15-15-35-T1 - 16-16-16-38-T2.

Can't get the reading past 22000-25000 GBps
Latencies are great at ~60ns.
Write speed abysmal, Read and Copy too.

New development: it seems that this problem occurs as soon as I apply XMP. At "safe default" the results are fine. Applying XMP or manually overclocking anything, even just CPU multi, kills it.

Didn't help setting high voltages. CPU C-states, turbo and power saving, etc. all OFF, no help either.

BIOS Defaults gives 58k.

________
It seems that 2800 is a bit too much for 128GB, at least in this instance.
While the CPU can clock high, 4.76@1.35, 4.88@1.4 (I never ran benchmarks on this, only Win boot), the IMC can't run 128GB @ 2.8GHz. I had to revert to 2.6GHz memory speed but so far it is fully stable with (CPU strap 125) BCLK 131MHz, 2620@14-14-14-34 1T, with default voltages. Which is very nice.
Will try going higher, but don't think it's worth the hassle.

[Arne Saknussemm]

Is that one single 128GB quad channel kit? or are you combining kits?

[orcinus]

Is that one single 128GB quad channel kit? or are you combining kits?

A single kit, of course. All other info seems fine, from the CPU-Z to AIDA's readings, BIOS... but performance is abysmal. I've started checking it out since I've noticed my copy operations and in-memory work are seriously slower than expected. AIDA results did not surprise me. I would expect the quad channel to be malfunctioning, but everything seems to be in order in that regard.

[orcinus]

This is the most default status I could setup; only XMP applied: http://imgur.com/a/zmUeL

And this is the result:
http://imgur.com/a/TlXQk

[Arne Saknussemm]

Sorry...had to ask...the of course one kit escapes a lot of people and you haven't updated your specs ;-)

Have you tried increasing vccsa to 1.2 or 1.25 and bumping dram voltage a bit too....just in case xmp leaves it on the edge of working?...maybe try 4 sticks only and see if things improve?

[orcinus]

Sorry...had to ask...the of course one kit escapes a lot of people and you haven't updated your specs ;-)

Have you tried increasing vccsa to 1.2 or 1.25 and bumping dram voltage a bit too....just in case xmp leaves it on the edge of working?...maybe try 4 sticks only and see if things improve?

Sys Agent to 1.2? Isn't it too high? Wasn't 1.15 maximum safe voltage?

[Arne Saknussemm]

Well...that's a debate...but fine for a quick experiment lots of people run 1.2...1.25...I wouldn't like to but at least you would know if it makes a difference and could plan from there..

Or...try running at 2400 MHz on 100 bclk and tighten timings...see if bandwidth improves...

[orcinus]

Well...that's a debate...but fine for a quick experiment lots of people run 1.2...1.25...I wouldn't like to but at least you would know if it makes a difference and could plan from there..

Or...try running at 2400 MHz on 100 bclk and tighten timings...see if bandwidth improves...

It did not... :/

[orcinus]

Reported theoretical bw is ~90k, but can't move above 23k I got with 1T from 22k... something is ... no idea.

[orcinus]

Memory: G.SKILL Ripjaws 4 Series F4-2800C15Q2-128GRKD DDR4 2800 MHz 128 GB Memory Kit - Black
BIOS: 3504
CPU: i7-5960X
OS: Windows 10 x64 Enterprise, fully/regulary patched
AIDA64 Extreme 5.90.4200
Applied XMP2
System Agent Voltage tested: 1.162V-175V
CPU Voltage tested: 1.02V-1.3V
Memory voltage tested: 1.35V-1.4V
Timings tested: 15-15-15-35-T1 - 16-16-16-38-T2.

Can't get the reading past 22.000 GBps
Latencies are great at ~60ns.
Write speed abysmal, Read and Copy too.