Intel newbie building ESX server - CPU recommendation for MB

[Beel]

I'm building a machine to test VM ware ESX, and the motherboard ( ASUS P5BV/SAS) I've selected uses an Intel CPU. All the machines I've had recently have been AMD, so I'd like to ask for opinions on which CPU to use.

I plan on using this machine primarily as a test environment, and a centralized place to store files to be backed up. As such, I the load shouldn't be heavy. At the same time, I would like to allow for some future expansion. Which brings me to my main question - Dual core or quad core? It looks like the Intel dual core server CPUs draw 65 watts, and the quad cores draw 95 or 105 watts. With the machine basically idling most of the time, will the quad cores be easy to keep cool? I don't know if I'll have need for quad core right now, but the future capability seems worthwhile. Please correct me if I've made any wrong assumptions. As I said, I haven't worked with Intel equipment lately.

Thanks in advance for suggestions and advice. Suggestions on CPU coolers would also be welcomed (if not off topic in this forum) I've been very pleased with the Thermalright that I've been using.

[frank2003]

Since you will be running vmware you want to make sure the processor you select supports hardware virtualization.

A cheap $50 AMD has hardware virtualization support. But for an Intel dual core processor you'll need to get something like an E8200 in order to get that feature. As rule of thumb, if the price of the Intel CPU is under $100 than it probably doesn't support HW virtualization.

[jessekopelman]

and the motherboard ( ASUS P5BV/SAS) I've selected uses an Intel CPU.

This is a server board intended for use with Intel's Xeon processors (albeit only the Socket 775 ones). I'm not sure if it would work with the non-server line (E8x00, Q6600, etc.) that give great bang for the buck performance. If you do need a Xeon, the dual-core E3110 seems like the best value; but is two cores enough?

[sjoukew]

If you are going to use more VM's simultaneously a LOT of memory and a lot of cores will really help improve the performance. I haven't got a lot of experience with VMWare and virtualization, but they say that for every virtual core you will assign to a VM, you need 1 real cpu core as well. Assigning a lot more virtual cores than you have real cores available will really hurt the performance.
Also when a VM idles it uses cpu power, so the assumption that 0% cpu usage in a VM is 0% cpu usage on your real cpu core is just not right. If I may make a really whild quess, I think every VM will use 10% of your real cpu, when the VM is running Idle. But keep in mind, this is only a really wild guess.
Seen from that perspective I would advise you to buy a quad-core with a lot of memory. I think a slow quad-core will be better than a quick dual-core.
And make sure that the cpu you choose has as much virtualization support as you can get, because it reallly helps improve performance a lot.

[Beel]

Frank,

Thanks for that tidbit. I rechecked NewEggs cpu list. You're right - There are a few cheaper CPUs and they don't support virtualization in hardware. I'll watch for that.

Since you will be running vmware you want to make sure the processor you select supports hardware virtualization.

A cheap $50 AMD has hardware virtualization support. But for an Intel dual core processor you'll need to get something like an E8200 in order to get that feature. As rule of thumb, if the price of the Intel CPU is under $100 than it probably doesn't support HW virtualization.

[Beel]

FWIW, one of the sources that suggested this motherboard, (which is a server board, as you pointed out) is using the board with a desktop version cpu. I'm leaning towards playing it safe, and going with a server version of the CPU. I've been to the ASUS site to check out the certified CPUs, and it looks like they've only verified the server versions.

This will eventually be a production machine and I don't want to chance losing billable time trying to save a couple of dollars. I looked on Newegg at the server CPUs, and agree with your choice for a dual core. Now I guess I have to decide whether to go dual core or quad core. Thanks for your thoughts.

This is a server board intended for use with Intel's Xeon processors (albeit only the Socket 775 ones). I'm not sure if it would work with the non-server line (E8x00, Q6600, etc.) that give great bang for the buck performance. If you do need a Xeon, the dual-core E3110 seems like the best value; but is two cores enough?

[Beel]

If you are going to use more VM's simultaneously a LOT of memory and a lot of cores will really help improve the performance. I haven't got a lot of experience with VMWare and virtualization, but they say that for every virtual core you will assign to a VM, you need 1 real cpu core as well. Assigning a lot more virtual cores than you have real cores available will really hurt the performance.
Also when a VM idles it uses cpu power, so the assumption that 0% cpu usage in a VM is 0% cpu usage on your real cpu core is just not right. If I may make a really whild quess, I think every VM will use 10% of your real cpu, when the VM is running Idle. But keep in mind, this is only a really wild guess.
Seen from that perspective I would advise you to buy a quad-core with a lot of memory. I think a slow quad-core will be better than a quick dual-core.
And make sure that the cpu you choose has as much virtualization support as you can get, because it reallly helps improve performance a lot.

Thanks for the advice. Could you elaborate on one point? What do you mean by "make sure that the cpu you choose has as much virtualization support as you can get"? I thought the CPU either supported virtualization or it didn't. Are there multiple virtualization features that I need to look for, or were you referring to multiple CPU cores? Thanks again.

[sjoukew]

Anandtech has a excellent article about different types of virtualization and the processor support. You will need some technical knowledge to be able to read it, however.
The different types of xeons from 2005 till now have different features helping virtualization, which are shown in a benchmark. The newest opteron and the coming intel nehalem have extended page tables, which should help in theory. Unfortunately there is no software yet to test the effectiveness of this feature.

Virtualization is a hot topic in the "server world" at the moment and there are a lot of developments in that area. Generally spoken, the more advanced the cpu is, the faster it works with virtual environments

[frank2003]

Also want to add that if you plan on expanding the system to include more than a quad-core processor per board (e.g two quad-core processors, a common config in a VM environment), you might want to invest in a Xeon quad-core instead of a desktop quad-core since only Xeon processors are multi-processor capable. If you decide to go this route just be aware that the two Xeons may need to have the same stepping (that was true in the early days of duallies; not sure if the same requirement applies nowadays).

[Beel]

Anandtech has a excellent article about different types of virtualization and the processor support. You will need some technical knowledge to be able to read it, however.
The different types of xeons from 2005 till now have different features helping virtualization, which are shown in a benchmark. The newest opteron and the coming intel nehalem have extended page tables, which should help in theory. Unfortunately there is no software yet to test the effectiveness of this feature.

Virtualization is a hot topic in the "server world" at the moment and there are a lot of developments in that area. Generally spoken, the more advanced the cpu is, the faster it works with virtual environments

Thanks for the clarification and the link to the great article. I have learned enough that I think I'll be ordering early this week. I appreciate your help.

[Beel]

Also want to add that if you plan on expanding the system to include more than a quad-core processor per board (e.g two quad-core processors, a common config in a VM environment), you might want to invest in a Xeon quad-core instead of a desktop quad-core since only Xeon processors are multi-processor capable. If you decide to go this route just be aware that the two Xeons may need to have the same stepping (that was true in the early days of duallies; not sure if the same requirement applies nowadays).

When dual CPUs were beginning to be mainstream, I think I remember reading the same thing about the stepping needing to be the same. I'm hoping for now that one quad is enough for what I plan on doing. Thanks again for your guidance.