Help with upgrading an old build

Hey everyone. I'm dropping in with a bit of an unusual one today.
My brother picked up an old PC as a gift—standard stuff—and naturally, he wants to mess around with it. He’s looking at nothing crazy, just things like COD 4, but it's currently a total non-starter. It's running an old Pentium 4 541 with integrated graphics that can barely handle a high-res video, let alone gaming. I've already managed to grab him a Core 2 duo E6600, but now I'm stuck on the GPU situation. We're looking at this BOARD. I spotted a Radeon 6670 on eBay, but there's a catch—the specs say it's designed for a PCI-E x16 2.1 slot, while our board just has a standard first-gen PCI-E x16 slot. Will this HD6670 actually run okay on our setup, or should I steer clear and look for something else? Our budget is incredibly tight, so we don't have much room for error.

Any advice?

Everything should be compatible since they use the exact same connector.

http://www.ebay.com/itm/graphics-card-listing

It really just comes down to how much they’re asking for that HD6670 DDR5; this one seems a bit more powerful than that.

I've got another question—why does every single game I try to run trigger an "error: send or don't send" prompt in XP, or just hit me with that "xxx has stopped working" message in Windows 7? It only happens when I'm using the PCI-E x16 2.1 slot; everything worked perfectly fine on integrated graphics. I've already swapped in two different cards and gotten the exact same result, so I'm starting to doubt the hardware itself is the culprit.

It might be a driver issue... I’ve run into this before when swapping an ATI card for an NVIDIA one on the same rig. Nothing would run—not a single game—until I did a full reinstall of the old ATI drivers. Strangely enough, doing it the other way around was never an issue.

Both cards are ATI—the first one's an x1950pro and the second is an HD6670. I ran into the exact same issue back on XP, except then it was just a "don't send" error. In the end, I went with the 6670 since I managed to snag an unused one on eBay for $67. It should be perfectly fine for 1280x1024 resolution, plus my case is so cramped that forcing the x1950pro inside was a total nightmare

Here’s another little headache. My BIOS is defaulting the processor frequency to 1.8 GHz when it really should be sitting at 2.4 GHz. I’ve already tried disabling EIST and C1E—no luck there—so the clock speed just refuses to budge past 1.8. I even attempted a bit of overclocking, but the best I could squeeze out was 2.34, which only nets me a 5.8 rating. Meanwhile, I’m reading online that people are hitting 7.1 with this exact chip. Can anyone help me figure out how to get back to that native 2.4 GHz? Staying stuck at 1.8 feels pointless—it's barely any faster than the Pentium 4 I had in here previously. 🙂

It’s not going to work. Processors with a 266 MHz FSB will be throttled down to 200 MHz on this board, meaning you're only getting 75% of the frequency you expect.
http://www.gigabyte.com/support-down....aspx?pid=2437

You really should have gone with an E4X00 series processor instead.

clocknut is sitting steady at 2.30—he pushed it to 2.34 once, but then he started losing his mind over it. Compared to an old Pentium 4, this thing is a different universe when it comes to gaming, apps, and just raw speed. It’ll be a solid interim setup until my brother saves up enough for a high-end rig—then I’ll be back to pestering you all to help him put together a beast of a build 😉)