What is the impact of a core overclock versus a memory overclock?

[atybimf]

Which has a bigger impact on FPS? I'm guessing core, but I don't know.

This question came to me when I was overclocking my x1900xt. I can do 650/828mhz on stock volts and I was wondering if that has as big of an impact as if I had the core really high and the memory near stock.

 

[AzNPinkTuv]

core im thinking as well

 

[KeithTalent]

Good question, I have always wondered this, but never thought to ask. I just assumed it would be the core that had the greater impact though.

 

[Matt2]

It depends on the video card. If the card is bandwidth limited, memory will do much more than the core. When memory bandwidth is not an issue, core clock is the bigger impact.

 

[Gamingphreek]

A core clockspeed increase increases pixel fill rate and the rate at which mathematical calculations can be executed.

A memory clockspeed increase increases memory bandwidth.

As Matt2 said if the architecture is bandwidth starved then memory will do much more than a core increase.

-Kevin

 

[BenSkywalker]

You can forget most of what has been posted above except the part about bandwidth limited will benefit from memory while computation limited will benefit from core.

You take any given board and run it @2048x1536 w/16xAF and then compare it to when you are running 1600x1200 w/4xMSAA and the former will be far more likely to be core limited while the latter will be more bandwidth limited. Certain architectures tend to be balanced in different ways, but no matter which part you are dealing with you can certainly hit situations where one or the other is the limiting factor.

 

[atybimf]

THanks for all the answers.

 

[d3lt4]

I'd say try each way, measure the FPS or 3dmark score, and then tell us all which one is better for FPS.

 

[TheRyuu]

Although your talking about the X1900, I can tell you that the 7900GT seems to like a core overclock better (but you can really push both of them up there).

As for your X1900, core speed is probably more important, but why not overclock them both.

 

[Extelleron]

I could tell you from my "experiment" (I actually did a 7th grade science fair on this) with my Radeon 9600, from stock 325/400 I oc'd to 425/400 & 325/500 (100 MHz each), and found the core made more of a difference. The memory made slightly, slightly more of a difference in 3D Mark 03, but in actual games the core made much more of a performance impact. Of course, as others have said, each card will be different, and also what settings you're using will make a difference as well.

 

[atybimf]

Alright, thanks. I run at 1280x1024 6xAA 16xAF (HDR as well in games that support it.) I think that the memory overclock on my card helps out alot in Oblivion with the settings I run at.