Core frequency, memory bandwidth, and pipelines... oh my!

[WAZ]

I've spent countless hours researching my video card purchase and have read and compared all the features and benchmarks my brain can process. I've narrowed my purchase down to a 6600GT (Leadtek or XFX... about $220) or a 6800 (plain... not Ultra or GT... BFG 6800 OC runs about $280). The aspects that confuse me the most are how important the core frequency, memory bandwidth, and pipelines are.

For example, the 6800 has a 256-bit interface, compared to the 6600GT's 128-bit.

The 6800 also has 12 pipelines to the 6600GT's 8.

However, since I'm talking about the vanilla 6800 and not the GT/Ultra, it appears to be hampered by 1) slower core (325 MHz, to the 6600GT's 500MHz), 2) slower memory (700 MHz to 1000 MHz), and it's only GDDR, compared to 6600GT's GDDR3.

Does GDDR versus GDDR3 matter?

Which is more important in the long run -- the 6600GT's faster core and memory speeds, or the 6800's more memory bandwidth and 4 more pipelines?

I've also heard of a system bottlenecking a video card, though I'm not sure how or what specs would cause that. I have an FX-55 with 512 MB of PC3200 DDR, so I don't know how this plays into the picture.

I don't care about a 5 FPS difference in Call of Duty or HL2 *now* -- the benchmarks between these two cards on current games are close enough that it doesn't matter to me. The extra $60 is also not a factor. But I do want to know WHY I'd be paying the extra $60.... if these things on the 6800 matter, and how/why its slower aspects compared to the 6600GT have an effect now, and in the future.

Sorry for the long question, but I'm really trying to figure out how a lot of this works. Thanks. 🙂

 

[Staz]

Just get the BFG 6800-OC from Outpost.com.

It's only about $30 more than your 6600GT, comes overclocked out of the box, and has a lifetime warranty.

And to partly answer your original question, it all depends on the resolution you run your games at. There will be little to no difference at low to mid resolutions. However, once you get to higher resolutions and turn on all the eye-candy, that's when the 6800 pulls away from the 6600GT.

 

[WAZ]

So why is the 6600GT considered so great then? I know it's supposed to be one of the best "bangs for your buck" right now... but if for $30 more there's the 6800......

I was definitely considering the BFG 6800 OC. Then I just bogged myself down with all these questions about why this vanilla 6800 is better than the 6600GT when it has a slower core speed and slower memory.

But those slower speeds on the plain 6800 apparently don't matter? They're made up for by the 256-bit interface/more bandwidth and more pipelines? Does that sum it up pretty well, or am I still missing something?

 

[WAZ]

Really, I'm mostly trying to figure out if a year or two or three from now, when the next generation of games with the newest graphics come out, what will they need? What will be better in the long run?

The higher core & memory speeds of the 6600GT? Or, despite those slower speeds on the 6800, the 6800's more bandwidth and more pipelines?

Thanks! 🙂

 

[otispunkmeyer]

and u want anotherstick of 512 to compliment that fx55 better

 

[WAZ]

Originally posted by: otispunkmeyer
and u want anotherstick of 512 to compliment that fx55 better

That's next on my list, eventually. 🙂

 

[uOpt]

Originally posted by: WAZ
So why is the 6600GT considered so great then? I know it's supposed to be one of the best "bangs for your buck" right now... but if for $30 more there's the 6800......

I was definitely considering the BFG 6800 OC. Then I just bogged myself down with all these questions about why this vanilla 6800 is better than the 6600GT when it has a slower core speed and slower memory.

But those slower speeds on the plain 6800 apparently don't matter? They're made up for by the 256-bit interface/more bandwidth and more pipelines? Does that sum it up pretty well, or am I still missing something?

There is not much that is slower on the 6800. 12 pixel pipelines at 350 MHz is almost the same as 8 at 500 MHz. Same for 3 Vertex pipelies at 500 versus 5 at 350 MHz. There are a few other unit where the 6600GT will be a little faster but the main units are the same speed.

The effective memory bandwidth is memory clock multiplied by width, so the 6800 just wins. There will be a few situations and access patterns where the 6600GT wins because it's not forced to grab 256 bit at a time (I think this is the case). Doing AA or lots of pixels it will always lose, but maybe it accesses small data structures like shader programs, vertex arrays or whatnot a little faster. I would expect that running future games at low resolutions you would be a little faster with the 6600 GT.

The reason that people thought the 6600 GT is hot is because the prices were supposed to be $200 for the 6600GT and $300 for the 6800. For a card practially as fast at lower resolutions and AA that would be a good deal. But supply and demand messed this up.