I'm not sure about the canadian price difference. But are far as I can see you would do great with more memory. When thinking of graphics performance in games you REALLY need to think about system ram and the video card. You might not need to get a new PSU. But going from 512 to 1024 is a huge boost to games. You really will see the difference. Add in a video card and you get even more performance. But being you plan on getting a XFX GeForce 6600GT AGP i think you should try for something better. Maybe wait for extra cash if thats a issue. There are two reasons for this.
1. The 6600 is good but a 7600gt or 7800gt are way better.
2. You don't wanna kick youself 6 months or a year later and have to get another card. Think about the future now. Oblivion is a demanding game, but even more demanding games are coming.
It is all about how much you wanna invest. But take into consideration that you seem to be playing games that really require alot of power. So you might as well be ready for the future.
where do you live in Canada? and where are you getting those prices from?
I live in Montreal and those prices come from www.ncix.com, which is the best canadian equivalent to newegg.com.
My actual psu is a generic 300W that only gives 13A to the video card, while a 6600GT requires at least 18A. So, I really need to upgrade that part.
From the benchmarks mationman refered to, we see that the X1600Pro does a fairly better job than the 6600GT; it actually beats even the 6800GT. The X1600Pro AGP is available for only 151$CAN; less than the 6600GT! However, I think in those benchmarks they are using the PCI-Express version of that card.
Wait! don't do it!!! Actually you can get a x800xl for about the same price, and if you compare it to the x1600 AGP on the video card performance chart you'll see it always (or pretty close to always) comes out on top. You may even consider getting the x800xt or x850xl if you can find them cheap enough. Trust me here though, you don't want the x1600 if you can get an x800 for about the same price.
you can get a x1600 512, too, for cheap, so that might be a consideration. x800xx can't do HDR last I knew & can't do SM3, yeah, that might not make much of a difference, but, then again, I don't know your image quality preferences. Also, the 512 versus 256 might now make much difference, but the price difference isn't much, so just in case...
Sorry cobber, but 512 ram on a slow GPU like a 1600 is called a marketing gimmick.....consider that both the new 7900GT and 1800GTO only have 256mb, and the neither the 800xl nor any 1600 has the grunt to run HDR at any reasonable res/settings.
I'm not anti HDR or SM3, but both are either too demanding or somewhat overated, so the best bet is to aim for 12x10 at very high settings and you'll have a great image.
I went from 512 to 1024 and from integrated to 6600GT on a P4 2.2 and was the best money I have ever spent in an upgrade. I would highly recommend you get the best video card you can afford, it is well worth it.
Not much I can say except to reinforce what others have said and recommend getting the best card you can. Good performance per dollar (Canadian or otherwise) is also important. Skip 512MB versions of low to medium range cards because it won't help much if at all. Probably either a 7600GS or an X1600Pro would do you well so get whichever is cheaper.