Hi,
Like many others, I had been frustrated with the poor performance I was experience using Second Life on my hardware. I wanted to post this so others can learn from what worked for me.
I had originally started on an eMachines T542, 2.5 ghz celeron, 256K RAM, with Intel's 3D Extreme Graphics AGP integrated chipset. It was a horrible experience. I then dropped in a no-name nVidia FX5500 PCI video card with 256M or RAM. The experience was less horrible, but still frustratingly slow. That was last year.
I recently purchased a Compaq Pressario with an Athlon 64 3500+ processor, 1 gig RAM and an Integrated ATI Radeon Xpress 200 video chipset with 256MB. I was getting frame rates of around 2-5, sometimes 10 FPS--a true dog of an experience. It was extremely frustrating because this machine should handle SL adequately. For $574 at Best Buy for the CPU, it was a fair price.
For other reasons, I returned the machine and decided to find a machine in the same price range that had an nVidia chipset, to see if the difference really mattered. I settled on a Gateway GT4016 for $599. Athlon 64 3700+ processor, 1gig RAM, and an nVidia GeForce 6100 integrated chipset with 256MB. This is essentially the same machine as the Compaq, with the only difference being the integrated video chipsets and a slightly faster CPU.
With the nVidia chipset, I'm getting frame rates between 15 and 30 FPS. This is very acceptable to me at this time. While not lightning fast like a big honking graphics card, this machine should tide me over for the next year or so without having to buy a new graphics card.
There's plenty of talk on these forums of how nVidia works great with Second Life and how ATI doesn't. At least between these two, comparable chipsets in May of 2006, nVidia is a much better integrated chipset than ATI for Second Life. If you're in the market for a relatively inexpensive machine, be sure to buy the one that includes the nVidia chips. You'll have a much better chance at a good SL experience.
Of course, a big honking graphics card should give you an even better experience.
Hope this helps with your decision on what machine to buy.
Kweisi Mfume