2P and 4P Systems

yottabit

Golden Member
Jun 5, 2008
1,357
227
116
Hey guys- hoping someone could help me get up to speed on multi processor systems since there doesn't seem to be a lot of focus on them lately (what with moar cores happening just fine on one package)

However it seems to me like if you really wanted a ~12 core system that didn't compromise at all on IPC, you could probably do that with two Intel Hex cores (such as the Xeon E5)

I remember these types of rigs were pretty common when things like the EVGA SR-2 motherboard were popular. But what are the more modern solutions?

It's very confusing to me because it seems not all Xeon E5's support 2P (even SB-E ones), I'm really guessing things like the 39XXk CPUs don't support it, and I don't really understand the benefits between SB-E, IVB-E and (Haswell-E?)? Are they IPC or just power consumption?

Do any 2P motherboards for SB-E or IVB-E support overclocking? At least bumping up all the cores to max turbo freq?

EDIT: Well I did some extra research and there are boards like the SR-X that support 2x Socket 2011, but from what I can gather you have to use Xeon E5's, and all the SB-E and IVB-E ones are completely locked down for overclocking -_-.

That really hurts the "bang for the buck" ratio when compared to something like an overclocked 3930k or 4930k

I guess the last question is are there any OS limitations to be aware of? Does Win 7 Pro only like a certain number of physical processors and/or max # of cores/logical threads?
 

ShintaiDK

Lifer
Apr 22, 2012
20,378
145
106
Forget 4P. And 2P boards doesnt OC as far as I know. I think a few can be done tho?

Win7 Pro supports 2 physical CPUs. Logical cores is 256 or something.
 

yottabit

Golden Member
Jun 5, 2008
1,357
227
116
Forget 4P. And 2P boards doesnt OC as far as I know. I think a few can be done tho?

Win7 Pro supports 2 physical CPUs. Logical cores is 256 or something.

I've still been looking into this, and the 2P boards I've seen that "Support overlocking" like the ASUS Z9PE-D8 will let you get to maybe ~104-105 BCLK on the Xeon E5s from what I can tell. Being able to overclock the ram could be important though.

It just makes it seem like it's not worth it compared to an overlocked hex core, unless you have applications that scale near-perfectly with each core and single threaded IPC isn't much of a factor.

Hopefully sometime soon we'll have a consumer unlocked 8+ core CPU from Intel... it's a shame, because if they at least made a version of the Xeon E5 that was multiplier unlocked, that could open up a whole new world for people.
 

ShintaiDK

Lifer
Apr 22, 2012
20,378
145
106
Only E5 2xxx Xeons support 2P as well btw.

Haswell-E will bring a 8 core CPU with a DDR4 requirement in Q3.

SB-E ->IB-E higher IPC, few new instructions, better performance/watt, more cores in the Xeon lines etc.

IB-E->Haswell-E higher IPC, AVX2, 256bit wide caches. And rest is to be seen.
 
Last edited:

zir_blazer

Golden Member
Jun 6, 2013
1,160
400
136
The problem with Dual Processor platforms is that they are very expensive with no added benefit unless you know what you will be doing with them. You lose overclocking capabilities (5 MHz Base Clock will not get you anywhere, really), and most high end Xeons models got more, but slower Cores, so for most task like games that doesn't go beyond 4 Threads or so, you're getting much below the performance of a mainstream Desktop platform even if you're dropping 2000 U$D per Processor.

Don't get me wrong. If money was no issue, I would go Dual just for the sake of having the biggest manhood in town. But besides that, it will be a pain in the butt to actually get to the performance levels that you should unless you use specialized Software that likes NUMA and all that. For everything else, is lower. And usually, you're discarding any sort of tweaking alltogether because BIOSes for serious Workstation and Server Motherboards doesn't let you run anything out of spec, even removing the first month of fun testing the capabilities of your build.
 

Stuka87

Diamond Member
Dec 10, 2010
6,240
2,559
136
What are you using this system for that you need so many cores?
 

yottabit

Golden Member
Jun 5, 2008
1,357
227
116
What are you using this system for that you need so many cores?

I'm trying to price out building some systems for simulation purposes

However the particular simulation apps have diminishing returns after about 8 cores but still somewhat decent scaling up to 16 cores. The big thing is that some stages of the solve processes are still single threaded so single threaded performance is still really important.

Hence if I could get something equivalent to dual 3930ks or 4930ks (overclockable), that would be perfect because it would be 12 cores uncompromising on single threaded performance. Unfortunately it looks like Intel is making us choose between cores and single threaded performance, which makes me sad.
 
Last edited: