Different processors on a dual socket motherboard?

[drethon]

Can you put two different processors (same family) on a dual socket motherboard? I want to do some work with dual processor development while still being able to use the PC for a gaming PC (not high end but capable enough). I'm looking at putting an Intel Xeon E5502 and Intel Xeon W5590 together as they are both Nehalem and the W5590 is very fast while the E5502 is very cheap and I can buy a second W5590 later if I get more serious about heavy duty processing.

I have a feeling it wont work but it never hurts to ask.

 

[cjl]

I don't think you can. I'm not positive about it, but I'd be pretty surprised if it worked.

You could just put a single W5590 in though - I'm pretty sure most multi-socket boards work with just a single installed CPU, and then you could add a second later.

 

[drethon]

I want the second processor so I can play with 8 cores (16 with hyperthreading?) and more importantly two separate processors without spending too much but also have one processor that is really fast.

If I have to though I'd rather buy one fast processor now and a second later when I can save up more rather than two slow processors now...

 

[MU_Engineer]

Can you put two different processors (same family) on a dual socket motherboard? I want to do some work with dual processor development while still being able to use the PC for a gaming PC (not high end but capable enough). I'm looking at putting an Intel Xeon E5502 and Intel Xeon W5590 together as they are both Nehalem and the W5590 is very fast while the E5502 is very cheap and I can buy a second W5590 later if I get more serious about heavy duty processing.

I have a feeling it wont work but it never hurts to ask.

The answer is that particular combination won't work together. Page 25 and 26 of the Intel Xeon 5000 Series Datasheet Volume 1 discuss mixing processor types. A brief rundown on what's supported and not:

1. CPUs must have the same QPI and RAM speed to work together.
2. CPUs must have the same thermal profile (TDP) to work together.
3. The CPUs must have the same number of physical cores to work together.
4. The CPUs must have the same number of logical cores to work together.
5. Stepping does not matter.
6. Clock speed does not matter.

If all of those are met, then you can run the CPUs together. The CPUs run at the speed of the slowest CPU. The current mix and match list:

1. Xeon E5502- can only work with another E5502 since it's the only dual-core Xeon 5500 (#4.)
2. Xeon E5504 can work with the E5506, both CPUs run at 2.00 GHz.
3. Xeon E5520 can work with the E5530 or E5540, both CPUs run at 2.26 GHz in either case.
4. Xeon E5530 can work with the E5520 (CPUs run at 2.26 GHz) or E5540 (CPUs run at 2.40 GHz)
5. Xeon X5550 can work with the X5560 or X5570, both CPUs run at 2.67 GHz in either case.
6. Xeon X5560 can work with the X5550 (CPUs run at 2.67 GHz) or X5570 (CPUs run at 2.80 GHz)
7. Xeon W5580 can work with the W5590, both CPUs run at 3.20 GHz)
8. Xeon L5506- can only work with other L5506s since it's the only L-series Xeon 5500 without HyperThreading.
9. Xeon L5518 can work with the L5520 or L5530, both CPUs run at 2.13 GHz in either case.
10. Xeon L5520 can work with the L5518 (CPUs run at 2.13 GHz) or L5530 (CPUs run at 2.26 GHz.)
11. Xeon L5508- can only work with other L5508s since it's the only 38-watt TDP Xeon 5500.

 

[drethon]

Ooh thank you, that's exactly what I needed

 

[ainarssems]

I remember playing with old 2 socket workstations from Pentium 3 days. It did work with two different processors but it run both processors at the slowest processors bus speed and lowest multiplier . I do not remember excact facts but for example if I had 666Mhz( 133x5) and 800MHz (100x8) then it would run both at lowest values bus at 100 and multiplier at 5 resulting in both running only at 500MHz.

It might work but there is no guaranty but both will run at slowest speed. There is a chance it will not work at all. There is too much difference between both speed, cache, QPI speed, core count. If it will work at all it will work like 2 E5502's.

I would just buy one for now and save up for second. Or even better buy 2 E5520

 

[MU_Engineer]

I remember playing with old 2 socket workstations from Pentium 3 days. It did work with two different processors but it run both processors at the slowest processors bus speed and lowest multiplier . I do not remember excact facts but for example if I had 666Mhz( 133x5) and 800MHz (100x8) then it would run both at lowest values bus at 100 and multiplier at 5 resulting in both running only at 500MHz.

That is still true according to the Xeon datasheet. The bus speed is 133 MHz for all Xeon 5500s, so only the multiplier will change. The two CPUs would thus run at the full rated speed of the slowest CPU if they are compatible with each other.

It might work but there is no guaranty but both will run at slowest speed. There is a chance it will not work at all. There is too much difference between both speed, cache, QPI speed, core count. If it will work at all it will work like 2 E5502's.

I would just buy one for now and save up for second. Or even better buy 2 E5520

I think that's good advice. The only non-identical CPUs that are still compatible with each other are pretty similar in price and performance anyway, so you're not able to gain much by mixing CPUs. You can usually pick up good server CPUs pretty inexpensively on eBay after they've been superseded by newer models, so I'd get two lower-end units now (a pair of E5504s or E5520s, perhaps?) and then upgrade to the W5580/5590 in a couple of years for pennies on the dollar for what they sell for now. You could also go the route of buying one fast Xeon 5500 today and then buying a matching unit later, but if you're going to do that, you're better off buying a Core i7 desktop today and then buying a used motherboard+dual Xeon 5500 setup later as it will yield the same performance at a much lower price.

 

[drethon]

I've got a few months before I actually put this system together so perhaps I can pick up something on ebay by then. I had not considered that but it makes sense that server hardware has more turnover than desktop hardware...

 

[aviat72]

Going by the above logic for the 5600 series, we should be able to share the 5620 and 5640 on the same system, right?


Spec Sheet
http://www.intel.com/Assets/PDF/datasheet/323369.pdf
http://www.intel.com/Assets/PDF/datasheet/323370.pdf

Processor Comparison
http://ark.intel.com/Compare.aspx?ids=47923,47925

All that changes is the multiplier.

 

[Mousemonkey]

This topic has been closed by Mousemonkey