Overclocking and Testing Methodology


The Asus N7800GTX TOP comes overclocked out of the box over the default frequencies on the reference card from NVIDIA. 

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At 486 MHz core and 1.35 GHz memory speed, the standard specs of 430 MHz core and 1.2 GHz memory from NVIDIA are looking pretty pale.  We are forced to wonder if perhaps NVIDIA was leaving a lot of room in the core for a future 7800 Ultra product line that may no longer be possible since so many of their partners are shipping overclocked parts well above the 430 MHz mark of the GTX.

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Of course, we couldn’t just leave the dials where they were, so I set to overclocking the GPU and memory speeds to as high as they would go without producing stability issues.  As you can see from the above screenshot, we got this card to 511 MHz core and 1.42 GHz memory speeds!  That is nearly a 20% increase in core clock speed and memory clock speed over NVIDIA’s reference specifications; simply amazing. 

Testing Methodology

Graphics card testing has become the most hotly debated issue in the hardware enthusiast community recently.  Because of that, testing graphics cards has become a much more complicated process than it once was.  Where before you might have been able to rely on the output of a few synthetic, automatic benchmarks to make your video card purchase, that is just no longer the case.  Video cards now cost up to $500 and we want to make sure that we are giving the reader as much information as we can to aid you in your purchasing decision.  We know we can’t run every game or find every bug and error, but we try to do what we can to aid you, our reader, and the community as a whole.

With that in mind, all the benchmarks that you will see in this review are from games that we bought off the shelves just like you.  Of these games, there are two different styles of benchmarks that need to be described.

The first is the “timedemo-style” of benchmark.  Many of you may be familiar with this style from games like Quake III; a “demo” is recorded in the game and a set number of frames are saved in a file for playback.  When playing back the demo, the game engine then renders the frames as quickly as possible, which is why you will often see the “timedemo-style” of benchmarks playing back the game much more quickly than you would ever play the game.  In our benchmarks, the FarCry tests were done in this matter: we recorded four custom demos and then played them back on each card at each different resolution and quality setting.  Why does this matter?  Because in these tests where timedemos are used, the line graphs that show the frame rate at each second, each card may not end at the same time precisly because one card is able to play it back faster than the other — less time passes and thus the FRAPs application gets slightly fewer frame rates to plot.  However, the peaks and valleys and overall performance of each card is still maintained and we can make a judged comparison of the frame rates and performance.

The second type of benchmark you’ll see in this article are manual run throughs of a portion of a game.  This is where we sit at the game with a mouse in one hand, a keyboard under the other, and play the game to get a benchmark score.  This benchmark method makes the graphs and data easy to read, but adds another level of difficulty to the reviewer — making the manual run throughs repeatable and accurate.  I think we’ve accomplished this by choosing a section of each game that provides us with a clear cut path. We take three readings of each card and setting, average the scores, and present those to you.  While this means the benchmarks are not exact to the most minute detail, they are damn close and practicing with this method for many days has made it clear to me that while this method is time consuming, it is definitely a viable option for games without timedemo support.

The second graph is a bar graph that tells you the average framerate, the maximum framerate, and the minimum framerate.  The minimum and average are important numbers here as we want the minimum to be high enough to not affect our gaming experience.  While it will be the decision of each individual gamer what is the lowest they will allow, comparing the Min FPS to the line graph and seeing how often this minimum occurs, should give you a good idea of what your gaming experience will be like with this game, and that video card on that resolution.

Our tests are completely based around the second type of benchmark method mentioned above — the manual run through.

Test System Setup

Each set includes a line graph and a bar graph.  The line graph still shows the performance over the span of time of the benchmark and the bar graph shows the data in a min/max/avg format that many readers like to see and are more comfortable with. 

You’ll also notice that I only tested the games we benchmarked at the 1600×1200 resolution.  While some gamers may not have the ability to run at that high of a resolution, it is really a silly notion to buy a $600 graphics card and NOT run at the highest frame rate possible that gives acceptable performance.  With the new 7800 GTX and GT, and even the 6800 Ultra and X850 XT PE in most cases, these cards benchmarked are fast enough that 1600×1200 isn’t in doubt and thus I feel that gamers OUGHT to be playing at this level having spent the money they did on such a product.  I am open to comments on this issue as well, so please, let me know how you feel on it.

We compared the Asus N7800GTX TOP in both default and overclocked configurations to the fastest 7800 GTX card we have tested previously here at PC Perspective to see if Asus could topple the current performance leader.   

Test System Setup


Asus 7800 GTX TOP (486/1.35)
Asus 7800 GTX TOP OC (511/1.42)
XFX 7800 GTX (490/1.30)


Athlon 64 FX-55


Gigabyte K8NXP-SLI

Chipset Driver



2 x 512 MB Corsair 3200XL

Memory Timings

2.0 3-3-6

Sound Card

Sound Blaster Live! Value

Hard Drive

Maxtor DiamondMax 10 300 GB

Operating System

Windows XP Professional SP1



ATI Driver

5.6 CCC

Software tested:

  • Doom 3 v1.3
  • Far Cry v1.3
  • Half-Life 2 Engine 7 (two maps)
  • EverQuest 2
  • 3DMark05
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