Has anyone here upgraded from Windows Server 2003 to 2008? For the applications you run on it, did you have any major performance loss?

In my case, I just did a simple experiment with an old P4 box. Win 2003 runs like a normal desktop OS would. It's pretty speedy at starting up and running a lot of our applications. When I changed the OS to Windows Server 2008, a tremendous difference occurs, the desktop slows down to a crawl.

The CPU usage spikes to 100% and the OS can barely function, let alone operate in that P4 box. Using it as a server, I experienced a tiny delay but I was the only client. I have no idea what would happen if I had thousands/millions of connections.

  • Why are you using a P4 still? If you have the potential of thousands of users, you need to seriously rethink your hardware. – ChaosPandion Sep 1 '09 at 23:10

Windows Server 2008 is defintiely more resource hungry than 2003; a base setup sits idly using about 400 MB of memory, while the same base setup with Windows 2003 uses less than 100. A DC/DNS/DHCP (standard infrastructure roles) uses about 600 MB, and again, to do the same with Windows 2003 less than 200 are enough. This is especially painful in virtual test environments, where you're going to use 600 MB of valuable RAM only to create a DC.

That said, Windows Server 2008 actually improves performances, if you have adequate resources; it scales a lot better than its predecessor.

For small/old systems (few cores, x86, less than 4 GB) Windows Server 2003 is still the best solution, unless of course you actually need 2008 features.

For large/new systems (many cores, x64, more than 4 GB) Windows Server 2008 (R2) is the best choice.


If it's running on a P4, I'd assume it's not on server hardware. If your hardware isn't on the HCL, I would fully expect to see performance issues.

I have a few IBM x3650s that were migrated from 2003 to 2008 and they are fine.


Personally I've dealt with both 2003 and 2008 and not seen any noticable difference in application performance. This is based on systems that are not using 100% of their memory and are using clean installs instead of upgrades - I don't trust upgrade installations for my home PC, so I certainly don't trust it for production servers. If you are short on RAM then 2008 will use a bit more which will cause problem. 2008 also requires more disk space than 2003- not an issue in most environments, but something to be aware of.

  • +1 for pointing out the Disk space requirements - where you could manage with ~20-30GB C: drives on Windows 2003, W2K8 needs about 50 over the medium term. I tend to set it to 60GB (+pagefile if that hasn't been moved) to avoid running into problems over time. – Helvick Feb 13 '10 at 18:25

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