Dual Core VS Quad Core

[jdoe1]

Were looking at purchasing multiple ESX 3.0 servers. However was wondering if anyone can answer what performance recommendations would be suggested.

HP Proliant DL380- Supports up to 2 Quad Core processers and 32 GB of ram.

OR

HP Proliant DL580- Support up to 4 Dual Core processers and 64 GB of ram.

If we decide to go with the DL380, were going to purchase the maximum amount of memory at 32GB which gives us no growing room but gives us the Quad Core processers.

If we decide to go with the DL580, we would start with 32GB giving us the ability to grow with memory with Dual Core processers.

Either way we would be at the same amount of processors DL580 4 Dual Core x 4 slots= 16 processors and DL380 2 Quad Core x 2 slots = 16 processors.

Can anyone advise what would perform better with ESX 3.0?

[admin]

1st of all

2X quad core is 8 cores

4X dual core is 8 cores

And more than likely 32G will be enough memory in either case, but it depends.

My personal experience has been that the (4) Dual-Cores will slightly outperform the (2) Quad-Cores.

Again, IT DEPENDS.

Message was edited by:

BrianG

[jdoe1]

Ah yes, sorry never was good in math.

[boydd]

How many vm's per host are you looking at? Have you also looked at the AMD offerings?

DB

[Paul_B1]

Here's the thing to remember. It's been our experience that the memory prices to jump from 2GB chips to 4GB chips make it not financially "worth it" to jump up. We currently use the 380G5's with 16GB RAM and 2 Quad Cores which come in at about $12k. To jump up to 32GB of RAM the servers would cost nearly $30k MORE (last quote I had). Same goes for the 580's. Just keep that in mind.

[petedr]

Here are a couple of good recent topics talking about Quad versus Dual Core.

We are currently using Dual Core DL385's.

http://www.vmware.com/community/thread.jspa?messageID=553152

http://www.vmware.com/community/thread.jspa?messageID=535187

http://www.vmware.com/community/thread.jspa?messageID=597993

[admin]

Paul - do you find yourself being memory constrained with this configuration? I have seen with these new quad cores in a small pizza box with only 16G leaves me running out of memory and having boatloads of CPU left.

Very good point though on the $$$$$$$$$$$ of the 4G DIMMS

[Paul_B1]

Yes, we typically DO have some left over processing power and memory is, I would say, always the "constraint" so to speak. However the fact that we can buy 3 servers with almost 3x the overall memory for the cost of just doubling the RAM in one box; and also, the fact that it allows us to "spread the risk" a bit (yeah ironic I know) across multiple boxes outweighs the excess processor capacity.

We did a lot of thinking about scaling up vs. scaling out, and these boxes seemed to fit the best for us and for the money. But again.. it depends on your goals

Message was edited by:

Paul.B

[meistermn]

Use HP585 G2 as 2 Socket (4 Cores) and 4 Socket System (8 Cores)

Tell them that the HP 385 G2 has only 8 Dimm ranks versus the IBM 3655

Look at page 41 at dimm 8 to 16.

http://download3.vmware.com/vmworld/2006/tac4057.pdf

You will get a HP585 G2 with 16 GB RAM for the sam price as a HP385 G2 with 16 DImm.

The other advantage with amd and 585 G2 is that you can use the quadcore processor barcelona which will ship in july 2007 and although you can use the quadcore processors in 2008, which will have i/o virtualisation.

[daat]

hi jdoe

not really of help but:

we bought 2 hp dl580 boxes with currently 2 dualcore cpus and 32 gig of ram

we dont have them running yet, im currently setting them up.

but i'd consider to take the dl580 because of the possibility to upgrade ram. its correct that the cost factor of changing from 32 to 64 is extreme, but i think in one year its not as bad as today. so you have the possibility to upgrade the memory in the future...

if you're running memory-intense vms on the esx box like we do, i understand your question too good...

[Freitag]

If the $$$$$$$$ due to Memory is such a big constrain, you should not forget the VMware licensing cost in your equation.

1 Dual Core Socket = 1 Quad Core Socket.

so using 4xDual Core you pay the double on VI3 Licensing as for 2xQuadCore, which is also lot of bucks.

[rock0n]

Due to the fact that the QuadCors are 2x2 CPUs and not real 4x1 CPUs there are some BUS limitations that will slow down the performance.

From my point of view i wouldn't set up a QC ESX if i need "High performance VMs"

[hicksj]

Yes, we typically DO have some left over processing

power and memory is, I would say, always the

"constraint" so to speak. However the fact that we

can buy 3 servers with almost 3x the overall memory

for the cost of just doubling the RAM in one box; and

also, the fact that it allows us to "spread the risk"

a bit (yeah ironic I know) across multiple boxes

outweighs the excess processor capacity.

I'm with Paul on this one. I am completely satisfied with the amount of VM's I can fit within 12-16GB of RAM. The cost of >2GB DIMMs is astronomical. I prefer to scale out, as each host per cluster allows higher overall utilization per host.

Some comments on the Quad vs Dual cores... The dual cores can be had with higher core clock speeds. Single-threaded processes are going to execute faster on the Dual Cores.

However, if you have VM's requiring 4 vCPUs, a 2xDual Core system (which is the current price/performance sweet spot) isn't going to cut it. To me, this is where the Quad's start making sense.

[jdoe1]

Thanks for all your unbiased opinions! I think it's fair to say that it's mixed feelings.

I think the end result is to go with a HP DL580 with Dual Core processors.

Thanks!

[admin · Accepted solution]

Joe,

Did you not find any of these responses as either helpful or correct?

If you did, it is customary to mark them as such.

Just push the "helpful" or "correct" button on the posts you found answered your question. You get to award 2 helpful's and 1 correct.

[petedr]

thanks for the helpful

[JonesVM]

There are some good points out there, most correct. We are evaluating dual core and quad core HPDL380's right now. The cost of 16-32 GB of RAM is pricy 12-13K more, or about double the price of the system.

However you need to figure the cost of VMWare $5700, plus support and assurance of about 22% per year. It starts to lesson that memory price gap. In talking with other companies and our TAM we are hearing about 4-6 VM per core. Sound a little agressive to me, but if you even get 3-4 more VMs for the extra cost of the memory and quad core, you are on the plus side of 3-4 more less physical servers. My .02

Risk is always a factor by having more eggs in one basket so to speak, but the chips and memory are only going to get cheaper.

[Yps]

Have a look at IBM 3650, 2U, and possible to use 12 DIMMs.

I have one with 2x 5160 Intel, with 24Gb, and I think memory is the bottenleck.

/Magnus