My first 5820k

[mackerel]

I'm sure this is ancient history to some of you, but it is new to me. I collected my cheap ebay 5820k from post office this morning, and the 240mm AIO just arrived so I've reassembled the 3x Crossfire setup with it... and the fun begins.

Currently I'm running it stock. If I run Prime95 it immediately current limits, and in XTU it is already as relaxed as it can be. I haven't tried poking in the bios yet. Package power is only reported at around 130W so that's not that high...

That aside, the ram in the system was 2133 since the Xeon didn't offer faster ram support. I had recently bought a 2800/3000 quad kit to split for other systems, so I gathered that up and put it in. Using it with Asrock X99 Extreme3 I don't seem to have much by way of memory multipliers. Is this a Haswell limitation? The ram is Corsair Vengeance LPX 2800, but it also has an XMP profile for 3000. If I select XMP1 2800, it wants to run 127 fsb, and for XMP2 3000 is chooses 125. I haven't tried either of those yet. IIRC the bus wasn't decoupled from everything else until Skylake was it? Sticking to safe 100, I can go 2666 or 3200.

Running some general stresses on it at stock at the moment just to verify the CPU before I leave ebay feedback and start overclocking it properly.

Oh, for the 3x580 thing, the firestrike score went up to 19500-ish, compared to 15000-ish with the previous Xeon. Direct comparison, still haven't turned off tessellation yet, and that was before putting in the faster ram.

 

[EarthDog]

Haswell-e will raise bclk for higher memory multipliers. This is normal. Your bios is at the latest for the board, right?

 

[mackerel]

I'm on latest bios. In some reading around, it sounds like there might be additional straps for PCIe bus, so increasing fsb might not be as risky as it sounds. At the worst, I can try it Just seems lacking compared to pretty much anything newer from Intel.

 

[EarthDog]

Well, the memory uses a strap to reach 125+ bclk. ACTUAL bclk range is still a few mhz. In other words, youll get 97-103 or 122-128 or 163-166 give or take.

 

[mackerel]

On newer systems, as well as having more memory multipliers, I thought that's why we have 100 and 133 ram straps... anyway, will go try it now. Worst case, I can get out my other quad kit of 3333 from my X299 system which runs easily at 3200.

 

[mackerel]

Ok, I'm cooking now. Not too literally... Fixed 1.25v and seeing how far it'll go on core clock. Just passed 42350 on Cinebench R15, but temps are getting a bit scary already. I think the Noctua D15 on my Coffee Lake system is probably better than the 240mm AIO I got and might swap them over.

Edit: Turned out when I thought I fixed voltage in XTU, it was still adjusting with clock. At fixed 1.25v in bios, I get 4375 Cinebench stable, crash at 4500. Temps are way better, highs below 70C now.
Edit 2: 1.30v only got me 4500. Going to 1.40 still doesn't get me 4625. Unless there is some voltage trickery I've yet to tap, that might be my limit.