How does 2x Xeon E5504 system compare with a 1x Xeon E5520 system?

While both solutions provide 8 threads, I would presume that 8 cores at 2.0 GHz will be faster than 4 cores at 2.26 GHz with Hyper-threading, but if your application(s) often use a single thread, then the E5520 with Turbo Boost will be faster.
http://ark.intel.com/Compare.aspx?ids=40200,40711,27468...,

GhislainG, thanks for looking into this!

I'm interested in the dual-processor E5504 server solution because: (1) dual-processor may be faster for running my data-base driven website (I expect to have a big MySQL database), but I'm not sure if this is indeed true; (2) it's less expensive than a single-processor E5520 server.

My concerns about the dual-processor E5504 server are:

1. Dell cites an example where E5520 has about 76% higher performance than E5504 in Microsoft SQL Server 2008 online transaction processing
2. E5504 has slower RAM speed (only 800mhz for E5504 vs. up to 1066mhz for E5520)
3. E5504 has no turbo boost or hyper-threading

I plan on using the server to run a website with a large MySQL database and lots of Php, Javascript, interactive content (forums, vidoe embeds etc.) and some Flash.

Which system would you recommend based on this info?

Many thanks for your help!!!  

To start with, Dell are correct about the E5520, but I presume that the Microsoft SQL Server 2008 OLTP test was with the same number of processors. Can you provide a link to it?

I don't think that 2 and 3 are a serious issue. Turbo boost won't help if all cores are busy and the RAM speed difference doesn't have a major impact. I'd certainly be more worried about disk I/O. As an example, using Nehalem processors for a large DB and a single SATA disk will definitely cause a disk I/O bottleneck.

GhislainG, here's the link to the Dell example - it's towards the bottom of the page:

http://www.dell.com/content/learnmore/learnmore.aspx?c=...

Another concern I have about the E5504 is the small cache memory - only 4MB vs. 8MB for E5520. Is this a serious concern?

You brought up a great point regarding the disk I/O bottleneck. Should I use multiple disks? faster disks? I'm looking at a disk with 250 GB 3G SATA7.2K. Would it be good enough?

I'm completely new to servers. Thanks again for your help!

Dell mention that they compared a single E5520 to a single E5504. Two E5504 would have been faster.

4MB for 4 threads on the E5504 vs 8 MB for 8 threads on the E5520. Two E5504 will have a total of 8 MB of cache for 8 threads. I may be wrong, but that looks quite the same to me. If you're going to use such a low-end hard disk, then why are you worried about the processors? You DB isn't large if you only need 250 GB for everything.

If the server supports SAS drives and if it has a SAS RAID controller, then use 10K or 15K SAS drives in a RAID 1 or a RAID 10 (much faster) configuration. If the server only supports SATA drives, then you'll probably be limited to 4 drives in a RAID 10 configuration. That will be better and faster than a single hard disk.

How fast is your Internet connection?

My internet connection is 2Mbps.

The 250GB "low-end hard disk" is part of the pre-packaged E5504 server to which I'm thinking of adding a second E5504 processor. The pre-packaged server does not support SAS drives and has no SAS RAID controller, but it may be added. I haven't bought the server yet, so any advice would be very helpful at this point (also taking into account my internet connection speed).

Thanks again!

With a 2 Mbps connection (I presume that's your upload and not your download speed), you still want a good response time, but you certainly won't have hundreds of users at the same time. I'm not so sure that you even need a second E5504 (it depends on the complexity of the queries), but I'd at least add a second hard disk and run them in RAID 1 mode. Reads will improve over a single disk and you'll have less risks of losing your data. If your DB is important, don't forget to back it up on a regular basis.

2 Mbps is indeed my upload speed, and I may get faster speed in the future to accommodate more users.

If I expect the user base to grow over the course of this year, should I then just go for the faster E5520 server (which also supports SAS drives and has SAS RAID controller) now so I have room for future growth, or should I wait until later to upgrade from E5504 to E5520 or to dual-E5504?

Thanks for all youe help! I really appreciate it!  

Upgrading later will probably be more expensive. It might make sense to start with the E5520. A SAS RAID controller is expensive and if you buy one, you want one with battery backup for optimal performance. I'd start with two SATA disks and upgrade later on if need be. You could still keep the OS and software on the SATA RAID if you wanted to and add a dedicated RAID for the database.

Based on my experience, I think that you might be over estimating your hardware requirements.

GhislainG, I'm a bit confused:

1. You said it "might make sense to start with the E5520" and then
2. Suggested I "start with two SATA disks and upgrade later on if need be"

In 2, were you referring to "upgrade" of disks only or were you suggesting processor upgrade?

Thanks for clarifying!

1. If your plan is to eventually upgrade to two E5520 processors, then it would make sense to start with one instead of one or two E5504 processors.
2. Both servers support SATA disks. With a SAS RAID controller, you can use SATA or SAS drives. If you don't buy the SAS controller right away, then you have no choice but to use SATA drives. If you decide to buy the SAS RAID controller, then buy 10K or 15K SAS disks.

Understanding the type of data and the queries' complexity would help. For instance, simple queries don't require much processing power while very complex queries are more CPU and disk intensive. I'm currently testing a server on a CPU that's much less powerful than an E5504. A relatively complex query (Oracle DB) took 45 seconds and the CPU utilization rarely exceeded 7%, but the SATA hard disk was very busy. Therefore I know that the CPU definitely isn't the bottleneck. If I use a hard disk subsystem that 5 times faster, then the same query will take a loss less time. Before making a final decision on your hardware, could you use a PC (physical or VM) with a SATA disk in order to try to determine where the bottleneck will be? You want to invest where performance can be improved.

Since I'm a complete newbie to servers, could you explain exactly how to do this? It's a great idea to test it out before deciding on the hardware - I couldn't agree more.

Thanks a lot for your help!

Use a standard PC (or a VM on a powerful enough server) and run your software. Monitor the system's CPU utilization and check the hard disk activity (or log it). If the CPU isn't that busy while there's a lot of disk activity, then you may want to invest in faster disks. If the CPU utilization often exceeds 60%, then you know that a faster CPU will help. In other words, if a 2 GHz Core 2 Duo (or similar system) is always waiting for the hard disk, then throwing more processing power at it won't help. Ultimately you want a balanced system for the tasks that you'll throw at it and you need to determine what response time is acceptable for n users, e.g., 1 second, 2 seconds, etc.

GhislainG, thanks for all your help!

I hope I'll be able to put all this info to good use. Thanks again!!!  

Thanks for the advice! Since this is my first server, I think I'll go for a basic - but balanced - system to get started. I'll get a E5504 with disks and RAM to match. Hope all goes well. Thanks a lot for your advice!!!  

Best answer selected by llww.