View Full Version : Single fast processor or multiple slower processors
04-15-2012, 09:36 AM
Looking for some advice on new systems. It used to be easy to know which processor to buy, just buy the fasted clock speed. Now with all the new processors out with multi-cores, I'm not sure. Would it be faster for a single 8 core (e5-2690) 2.9ghz or dual 8 core (e5-2650) 2ghz? Also, say I buy a HP Z820 with a single (e5-2690) 2.9ghz processor and down the road I want to add another processor, will a off the shelf Intel processor work or do I have to buy a processor from HP? I'm looking at them now and there's a huge difference in price. HP wants $3700 to add another e5-2690 when I can buy that chip direct for $2100. I know most of you will say build your own system from scratch but I'm a DP and editor, not a computer guy and don't have a dedicated IT dept. Any advice would be greatly appreciated.
04-15-2012, 01:09 PM
It depends largely on how well multi-threaded your usage scenario and preferred software(s) is. You have to consider it this way - a single 8-core will get you 8 cores and 8 more hyperthreads at 2.9 GHz. The dual 8-core will get you 16 cores and 16 hyperthreads at 2 GHz. Premiere Pro can only leverages 16 threads (adjusted for hyperthread leakage), at most, for R3D playback, hence the single E5-2690 will offer superior performance today, upto 30% or so (yes, I am accounting for Turbo here).
However, looking to the future, it is possible a future R3D SDK will saturate all 32 threads, in which case the dual 8-core E5-2650 will get you a straight 25% increase over the single E5-2690. Even today, something like X264 will see similar gains. On the other hand, if an application can use 32 threads, AMD's Opteron 6200 are fabulous choices, offering 32 cores for the price of Intel's 8 cores - that is why most of Cray's supercomputers ditch Intel in favour of AMD when it comes to massive multi-threading. But that's off-topic... By the way, E5-2670W is a better choice if you are going single CPU. (faster, cheaper at the expense of more heat, but you are saving much more of that by going single CPU)
There are also other things to be considered specific to the HP Z820 - is the single CPU option using a crippled dual socket motherboard with one socket disabled? That can have implication on memory bandwidth, QPI bandwidth etc.
04-15-2012, 01:35 PM
I faced this dilemma about a year ago and sort of split it down the middle. I am a "Mac guy" (and not a computer "expert" by any means) and so ended up with a single processor Mac Pro - 6 cores/3.33 GHz clock speed. At the time, a lot of software didn't make very good use of the cores so I opted to get the fast processor rather than go 8 or 12 cores. Things have changed a little and no more software can take advantage of the cores. As stated above, it depends on your needs now and what you anticipate in the future. My decision remains a pretty good one for me but it is a moving target. I might err on the side of more cores if I were making that decision today.
04-15-2012, 05:26 PM
To add to what Subhadip said, there are a couple other considerations here. The PCIe controller as well as the memory controller are in the CPUs. So on the z820, you will need both CPUs installed if you want to maximize your memory bandwidth and make use of all 16 memory slots. You will also need both CPUs if you need to use most or all of the PCIe slots. If single CPU is a real option for you, then you may want to consider the z620 instead.
For a single CPU I would recommend the 2670W or 2687W. They do suck a bit more power, but are better and a bit cheaper than their 135W counterparts like the 2665, 2690.. Actually the 2687W is the one E5 CPU I recommend the most. Watch out though, HP is charging an arm, leg and kidney for these systems. You can get 20% off with the coupon online, but their still brutally expensive.
I would recommend buying with the lowest graphics option, or none, and installing a GTX580 yourself. Unless you need the Quadro card, but they're charging too much for them.
04-15-2012, 07:54 PM
Thanks for the input guys. No kidding on the arm and leg thing Jeff! Like $9500 for a dual 2687 and you can't configure the z820 with a single 2687. Back to the processor question. Any idea if a off the shelf e5 processor will fit right in the z820? If so, I think I'll just bit the bullet and buy single processor z820s and get another processor from NewEgg and drop it in. Saves us about $1600 per box. Terry, we were a Mac shop a couple of years ago but moved to HP z800's. Miss the simplicity of the Mac Pros (they always just worked) but you just can't beat the raw power and RAW workflow in Sony Vegas (our editor of choice now for the Red workflow).
04-21-2012, 02:14 AM
I have always gone Dual CPU.
04-25-2012, 09:44 AM
Titanus computers seems to have much better deals then HP.
04-25-2012, 10:52 AM
Titanus computers seems to have much better deals then HP.
Compared to what specifically? They're building those systems out of 100% off-the-shelf parts, several of which I would never choose myself. While one can install a XEON E5 on those motherboards they're offering, that's somewhat silly as they should be running on a C6xx series chipset rather than X79. Went back a level and saw they have their X495 model dual Xeon E5 box. I went in and configured it the same as the HP Z820 I've got on order (less the water cooling) and the Titanus was only $218 cheaper. But like I said, there wasn't a way to add the water cooling. Compared to the Supermicro X9DAi systems I'm assembling (as parts trickle in), the Titanus was coming in at a good $1500 more. HP is priced decently if you know how to navigate their [pain in the ass] ordering system and apply all the coupon codes, which are always there to bring their systems into the realm of normalcy. IMO, if I'm going to buy a system made out of all off-the-shelf parts, I'll just assemble it myself.
As for the Z820 it looks good, but I'm still waiting for mine to ship. Getting pretty frustrating, it was supposed to ship last week....
A tip for anyone building or buying workstations and looking to install Quadro or Tesla cards -- buy the white-box OEM versions. It will save you $1500 on a Q6000 or C2075, you'll just have to pick up the $3 PCIe and SLI cables separately if you need them. Technically, they're only supposed to be sold with new system builds, but some vendors will sell them alone. I ordered my Z820 without a video card, but it's going to be up and running with a Quadro 6000 plus an EVGA GTX580 Classified Ultra (900MHz OC'd) for a Resolve GPU. I paid less for the Quadro 6000, GTX580 and a 512GB Vertex4 SSD than HP wanted for the Quadro 6000 alone, even after their 20% coupon and 2.5% preferred discount. ;)