GPU Overclocking Decreases Minimal Frame Rates

Interesting data – Raimondas Rimkus

Important: I don’t really know what influences this and why this is happening. This is in my PC, but this doesn’t mean that it will be in yours too. If you have more info about this, please email me.

The first time I saw this was when I read an overclocking review in a journal. You could see in all those graphs that overclocking decreases minimal frame rates. I thought that this was a grammatical mistake. During my first video card overclock, I remembered this and checked if this is true – and it was… GPU overclocking really decreases minimal frame rates (this means that games lag more) although average frame rates still increase.

Here you can see how everything looks:

As you can see, the graph says the same – 175-210 is the GPU speed in Mhz. Going to 220 Mhz simply made my system crash. It’s hard to see it from the graph, but I can say the highest minimal point is at 195 Mhz. This was made with standard cooler and 300W PSU – my +5V line was as low as 4.71V and the GPU cooler was pretty damn hot. This isn’t the best environment for overclocking, so I bought new PSU (real 480W) and VGA cooler (Zalman ZM80C-HP with ZM-OP1).

I tried again with new setup:

The new VGA cooler and PSU allowed to overclock to 240 Mhz. But also, now the highest minimal point was at 225 Mhz (220 Mhz in summer).

So, why you should care about this? The answer is that at 230 Mhz, games really don’t feel so stable as at 220 Mhz. And also you won’t feel any difference between 45 and 60 fps, but there’s a lot of difference between 10 and 15 fps.

I also noticed that this strange effect doesn’t exist for video card memory. Memory overclocking gave stable, minimal frame rate increaces till it crashed. This means that it doesn’t work for all the component overclocking. I don’t have any possibility to check this with FSB, CPU, memory and everything else. And also I don’t know how too much oveclocking can show for the CPU and others.

Because minimal frame rates already got my attention, I noticed few more things:

I think that minimal frames should get more attention than testing, because then you try to compare ATI to Nvidia. With the same price and average frame rate, Nvidia usually wins, although ATI has way more stable frames. I haven’t tested it, but I do feel this way.

I also noticed that minimal frames are very sensitive to good Windows and BIOS configurations. Good component brands, huge amounts of memory, good cooling and a perfect configuration can get you rock solid gaming.

My PC specs (just in case):

• AMD Athlon XP 1900+ (at 42ºC, not overclocked)
• DFI AK75-EC Motherboard
• Daytona Geforce 3Ti-200 64MB
• 384 MB Ram
• 480W PSU
• WD 80 GM 8 MB cache 7200 rpm

So check this, run some tests and try to find out if you haven’t overclocked too much and email me if you find something new.

Raimondas Rimkus – Lithuania