Xeon 5500 series vs. i7

[borgmeyer]

Our office is looking into purchasing (4) new desktop workstations, primarily for Revit use. Our price point is +/- $2,000 / system and we usually use our systems at least 4 years or more. I've been looking at a couple of systems from Dell. I'm trying to decide whether or not to go the Precision T3500 / Xeon E5520 route or the Studio XPS 435 / i7 940 route. From what I understand the Xeon 5500 series is essentially the i7 processor with support for ECC ram and a slightly faster system bus. From what I've read the Xeon processors are more reliable than their consumer brethren. We don't do much rendering now, but hope to eventually get into it. On both systems I have 12GB DDR3 1066mhz RAM and Vista 64 (which I'll upgrade to Win7x64 after Oct. 22)

What are others' experience between these two processors? Experientially we have some older systems still in the office - some use dual Xeons (6 years old) and some use P4 or Core 2 Duo chips - the Xeons never seem to have any strange problems. Is the ECC ram worth that much more? The precision line definitely looks built to take a beating, but we really get the value out of it? Another thought was to go with a Precision T5500 which can take two Xeon chips - which we could upgrade ~2 years down the road when the chips have fallen in price and general use Revit is finally coded to used more than 1 core.

Any thoughts / advice would be much appreciated. Thanks.

[clog boy]

Benchmarks say the i7 is about 1.5 times as quick as the Core2quad. That's all I know for sure.

The core2quad can multitask and automatically balance the processes over it's four processing cores. If you get into rendering, Mental Ray will use maximum four cores.

The i7 processor utilises 8 cores and I think that process balancing has evolved with it. If you're using a post-XP 64bit operating system (either Vista or Windows 7) then you might also get maximum efficiency out of each core with the amount of RAM you're using. Based on that, I would say that you could reliably render a file, and run Windows and at least two more Revit sessions without experiencing much of a performance drop. Or you could render with two Revit sessions while Windows is idle. If my estimations are right then two simultaneous renderings will only take 66% of the time a Core2quad needs to render one file.

My guess is that i7 processors are only viable if you have many programs open at the same time (Navisworks, AutoCAD, Revit, Internet Explorer, 3D Max) and if that's your most likely scenario then you might want to spend the big bucks and go with Xeon for that few percent extra horsepower and reliability.

[borgmeyer]

clog boy, thanks for the comments. I'm not sure how the Core2Quad compares to the Xeon 5500 series, however from my reading the Xeon 5500 series is more similar to its i7 consumer counterparts. I think I would typically disable hyperthreading in the bios so that a system would only be using the number of physical cores - which currently seems to be the max for one instance of Revit / 3DS Max while rendering. We can always turn hyperthreading back on if more cores are supported or we need to do two instances of Revit rendering.

I guess my main question is regarding the ECC RAM with Xeon vs. no support of ECC on the i7 chips. A quick Google found this info about ECC:

ECC stands for "Error Correction Codes" and is a method used to detect and correct errors introduced during storage or transmission of data. Certain kinds of RAM chips inside a computer implement this technique to correct data errors and are known as ECC Memory.

ECC Memory chips are predominantly used in servers rather than in client computers. Memory errors are proportional to the amount of RAM in a computer as well as the duration of operation. Since servers typically contain several Gigabytes of RAM and are in operation 24 hours a day, the likelihood of errors cropping up in their memory chips is comparatively high and hence they require ECC Memory.

So it sounds like the more RAM we add to a system, such as a 64-bit system that opens large Revit files, the greater the need for ECC.

Your point about reliability might be worth alot to me - I'm officially an architect, but unofficially the IT guy for our ~15 person firm. The less I have to fix problems, the more I can get my own work done.

[ws]

FWIW I'd always bought Xeons in recent years but the i7 versions weren't available when I bought an i7 new PC earlier this year.

Thus no ECC memory and for the first time I can remember in years I had faulty memory in the new machine which took weeks to track down.

ECC can still be faulty as I understand it but it copes with minor errors and it runs a little slower.

Intel seem to aim Xeons at server rather than desktop use but I've always bought them for reliability and not been disappointed - albeit they cost a bit more and have tended to have noisier fans and server cases.

I leave hyperthreading enabled in my core i7 - there seems little point in disabling it.
Revit 2010 64 bit runs perfectly for me on Vista 64 on this machine.

[borgmeyer]

Regarding Hyperthreading, it was my impression that it in essence halved the processing power of a single core, by reserving half of it power for each of two threads. If this is the case, then hyperthreading would decrease the speed of non-rendering Revit actions.

Please correct me if I'm wrong. Does hyperthreading work more dynamically and allow the distribution of processing power more dynamically based on the threads sent its way? Thanks for any clarification.

[ws]

Umm, I'm no expert but I think the Core i7 version of HT is more complex than that in the way load balancing is done - it happens very rapidly - apparently too rapidly to always show up in Taskmanager.

The only comment I've seen about HT on i7 is that when overclocked, turning off HT can help keep core temperature down.

It came enabled on my new PC and so I've left it alone and it all works great in Revit and 3ds max design 2010.
I doubt you would see any benefit in such as Revit by disabling HT.

[need4mospd]

I've given my thoughts on this a couple times before here. Here's the quick summary based on some extensive testing and research...

The Xeons are a waste of money for Revit. There's some hype attached to them because they're expensive and more reliable, but they are not any faster or more reliable in my experience. My i7 has been up and running for 10 months with ZERO crashes. The Xeon in our office(quad version) does fine, but it cost twice what the i7 did and really isn't any faster, in fact it's a bit slower. The i7 smokes, even with only 1/8 cores running in Revit. If you look into overclocking, which I highly suggest, the 920 is hands down the best value processor on the market. No need to spend $2000 on a computer. Once you roll over $1000, the performance increase isn't really justified to me. Spend that extra money on a nice mouse and quality monitor and you'll be 10x happier.

Take that for what it's worth, just my experience...

Also, I ran some benchmarks in 2009 64 that showed ZERO difference disabling HT on the i7. I couldn't get it to run any faster or slower, even disabling virus software and all other background programs, or starting up every program I had. It just chugged along like nothing happened. It's a rock solid processor.

[borgmeyer]

need4mospd, thanks for the input. However, we just placed the order yesterday for (3) Dell Precision T3500 systems based on the Xeon W3540 2.93Ghz processeor, which uses the same core as the i7's. Honestly, the users getting them will have to work really fast to take advantage of the horsepower, but we'll be using these for some time.

Regarding hyperthreading, I did some testing on some older Prestonia Xeon machines. The setup was (2) 3.06Ghz Xeon Prestonia's, varying whether or not hyperthreading was turned on (i.e., 2 cores vs. 4 "cores"). Using the 2009 benchmark, hyperthreading trimmed off about 40 points, but these are both 500+ scores. I imagine that in the i7's case, since Revit is only capable of using up to (4) cores, turning on hyperthreading wouldn't make much of a difference unless you had other processor intensive apps going on at the same time. It also appears that from your results that processing power of each virtual core is not diminished when hyperthreading is turned on.

It has always been my impression that software is usally about 5 years behind fully utilizing hardware. Out of curiosity, do you build your own systems, or do you use a manufacturer that allows overclocking? Thanks for the input.

[need4mospd]

need4mospd, thanks for the input. However, we just placed the order yesterday for (3) Dell Precision T3500 systems based on the Xeon W3540 2.93Ghz processeor, which uses the same core as the i7's. Honestly, the users getting them will have to work really fast to take advantage of the horsepower, but we'll be using these for some time.

Regarding hyperthreading, I did some testing on some older Prestonia Xeon machines. The setup was (2) 3.06Ghz Xeon Prestonia's, varying whether or not hyperthreading was turned on (i.e., 2 cores vs. 4 "cores"). Using the 2009 benchmark, hyperthreading trimmed off about 40 points, but these are both 500+ scores. I imagine that in the i7's case, since Revit is only capable of using up to (4) cores, turning on hyperthreading wouldn't make much of a difference unless you had other processor intensive apps going on at the same time. It also appears that from your results that processing power of each virtual core is not diminished when hyperthreading is turned on.

It has always been my impression that software is usally about 5 years behind fully utilizing hardware. Out of curiosity, do you build your own systems, or do you use a manufacturer that allows overclocking? Thanks for the input.

I'm sure you'll be happy with the Xeons, they're solid for sure, just pricey!
The 2009 benchmark ran in 180 and 181 on the i7 switching between HT modes. Rendering uses all 8 cores, but they're only running at 50%. W/o HT they're 4 cores at 100%, but there was no significant time difference.

The software is definitely behind here. Once Autodesk finally catches up to the 21st century, these 8 core machines will be screaming fast. I do a little of both, depending on the price I get! I got my i7 at home from Dell for about $200 less than I could build it for in December last year. Kinda regret it because it can't be overclocked. My friend built his own for a little more and gets significantly faster framerates in games and render times up to 30% faster.