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Using Viewperf to Compare Graphics Performance

I could say quite alot on this subject, but for the moment here's something to bare in mind when reading Viewperf results:

Basically, if the main CPU is not the same then the benchmark figures are hard to compare and statistically unreliable. A good example is comparing the following two systems (I bet someone, somewhere, has made this particular mistake in the past):

Suppose you currently own system A and have just received a data sheet for system B. You're browsing through the polygon/sec, XLines/sec (etc.) numbers... how do you know these differences are down to the new graphics system (Extreme) and not the fact that System B was tested with a faster CPU? Often, the CPU used in the test is listed in small print somewhere and it's almost always the top of the range available. Like as not, you'll be considering a graphics upgrade, not a graphics + CPU upgrade.

Viewperf is a nightmare when it comes to this aspect of graphics performance. If you check the SPEC web site, then for a particular system (eg. Indigo2 or AlphaStation) you will find:

Naturally, PR people can use this to great effect. Digital did this on one of their AlphaStation/Indigo2 comparison WWW pages: they mixed performance results from Viewperf data that came from different Indigo2 configurations which had been submitted to SPEC by SGI. For each metric mentioned, they took the worst aspect from a particular configuration and used that in the table shown. The end result? The table implies that the data is from the Indigo2 system which they said was tested, when in fact much of the data came from Indigo2 systems with slower processors, less memory, older graphics options and outdated performance figures.

All in all, the particular page in question had over 10 factual inaccuracies and more than 15 logical combinational errors.

Don't get me wrong though: I've no doubt that every workstation vendor gets up to this kind of PR nonsense, but if you're going to use Viewperf and other published data when making a purchasing decision then you must make sure you know what it is you're actually looking at, especially if the data comes from a company web site.


Ian's SGI Depot: FOR SALE! SGI Systems, Parts, Spares and Upgrades

(check my current auctions!)
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