ATI X1800XL Video Card Overclocking Guide

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Testing and Results

For testing purposes I used the following system:

Test System:

AMD Video Card Test Platform



Live Pricing


AMD Athlon 64 3700+


DFI NF4 Ultra-D


2GB Crucial PC-4000

Hard Drive

Western Digital Raptor 74GB


Vapochill Micro

Power Supply

OCZ PowerStream 600W

Operating System

Windows XP Professional

Just a reminder that testing was performed with 100% video card fan speed to prevent overheating. Here are the results of voltage scaling.

X1800XL Voltage Scaling

Wow! We have reached the same core speed as the X1800XT, though the memory would not clock up to the 750MHz of the XT. Trying to go any higher meant that we would need more voltage, and created more heat than we were willing to accept. Let’s take a look at what this provided us..

3DMark scaling

Even with 50 MHz less core speed the overclocked 1800XL posts slightly higher scores than the 1800XT! We can only speculate that the memory timings are more aggressive on the 1800XL which is why you see equal performance even though it’s at a lower speed. Here is the chart from our last review for comparison.

3DMark 05 results

So, with a little bit of time we’ve been able to extract equal performance from our less expensive card. Our 624/700 settings were stable for all of the gaming sessions we put it through and no artifacts were present. If after gaming you want to return your card to normal you can simply go back to stock settings by clicking “default” in ATI Tool, and by setting the voltage and fan speeds back to their normal values. Or you could also just reboot.

Legit Bottom Line: If you are willing to sacrifice the Warranty of your brand new card then overclocking is well worth the effort. There is a very noticeable speed boost in all games. One final note, we do recommend that for peace of mind and an investment in the life of your card that you spend a few dollars on an aftermarket cooler.

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