by Shui-Che Lim
Letter 1: from Dr. R. West
I've been reading your Tech Talk column, I think much of what you say is quite sensible, but I do have a problem with what appear to me to be wild extrapolations. For instance you've said that...
"If you're currently running even a run of the mill Pentium 166, a single Voodoo 2 will give you 70 FPS under Quake. Dual Voodoo 2's will pump that up to 140 FPS."
How can this even begin to be true. The benchmarks at Toms Hardware show 47fps for a P200MMX, 35fps for a K6 233 and 23fps for a 6x8MX 200, with a single Voodoo II board. As a wet finger estimate I guess the P166 to give about the same FP peformance as the 6x86MX, maybe a shade more, ie. 25fps would be a reasonable claim, not 70fps.
Adding a second V2 does not necessarily double the frame rate. It increases it for sure, but I'd be very surprised if anybody could find a real world game where it achieved a doubling of the frame rate. A doubling in potential almost never translates to a doubling in reality in the computer scene, there's always some other overhead which limits performance. Doubling the wrong number doesn't help either.
I've seen other examples of this silliness on combatsim.com, not committed by yourself. Please be more careful when extrapolating. If you stand by your figures please present some evidence that what you say is correct, beyond the anecdotal.
Regards, Richard West.
Dr. West,
Keep in mind that the benchmarks on Tom's Hardware Page, while informative, are only applicable to his setup. He was running under Windows 95. If you check out this little quote on Operation 3Dfx, you'll see that Tony Tomasi and Gary Tarolli said that they were getting 67+ fps on a Pentium 166 running under NT. The URL is NEWS with the heading Voodoo 2 Update.
I will admit that I goofed with respect to Quake since Combat Simulations, as a general rule, doesn't cover software from that genre of gaming. I failed to notice that Quake, and most first person shooters for that matter, is heavily triangle limited. In this case, you are correct to state that a second Voodoo2 card would not make much of a difference to overall performance.
However, this is again entirely different in combat simulations. Current simulations see huge improvements to performance using just Voodoo cards while depending solely on the CPU for geometry transforms and triangle setup. This suggests that sims are more fill-rate limited as Voodoo, for the most part, increases fill rate performance. Even current sims such as Longbow 2 and F-22: ADF get quite a performance boost with Voodoo.
I've also asked the developers of simulations about the number of polygons they're generating per scene. The average is somewhere in the 8K-12K region per scene in games like Longbow 2 and F-22: ADF. However, games such as Quake and Quake II could easily double this number of polys or more. Based on this information, I have come to the conclusion that sims in general are less triangle limited and more fill-rate limited.
It is true that you won't see double the performance with dual Voodoo2's for all games. But for games that are more fill-rate limited, as I believe most sims are, dual Voodoo2's will certainly show a marked improvement over the performance of a single Voodoo2.
Shui-Che Lim
Letter 3: from BonyJoe
What would be the CPU of choice for mid 1999? Will the K7 outperform the Merced or will the Merced simply be too expensive for the average user? Or will the Merced come out on top and be within reasonable price range? Thanks.
K7 will most certainly outperform Merced in mid-1999 since Merced won't even be available in that timeframe :-) Actually, K7 is a clean sheet design and AMD aims for it to be a no compromise performance solution. Based on what I know about K7, it will kick the sh*t out of any Pentium II part of comparable clock speed that Intel cares to throw at it.
Sincerely, Shui-Che Lim
Letter 3: from Adrian
In regards to your "Beating the Performance Curve" article, which makes a great deal of sense to me, I wanted to ask if it made sense to you that since my current motherboard is unable to be upgraded higher than the 166 I currently have, wouldn't it make the most economic sense to get a P-II motherboard and a P2-233 CPU for now, then upgrade to a P2-300 or higher when the cost comes down? I think it may be silly to buy a new socket 7 just to get a P-233 MMX...
Also, the CPU prices you listed in your article are significantly lower than those I have seen online - can you tell me what mail-order company offers those prices?
Thanks for your time, Adrian "Fireball" LaVallee
There are many companies that make upgrade daughterboards that plug between your socket and the CPU that allow you to use the newer split voltage CPUs such as the AMD K6-200/233 and Intel Pentium 200/233MMX chips. So you can still use these chips without throwing away your current MB. What you won't be able to do though is to overclock these chips since your board probably doesn't suppor the higher bus speed or clock multipliers... so you'll just have to make due with running the chips at their rated speeds.
Whether or not to go to a Pentium II depends on how much money you're willing to spend. As much as I hate to say so, if you're going to do a whole system upgrade then it might make more sense to go to a Pentium II. I only mention Super 7 because many people have more recent CPUs already and don't want to upgrade their whole system infrastructure.
However, if you main use of the system is for combat sims, then the good news is that a recent 200MHz/233MHz AMD or Intel processor with dual Voodoo2's would give more than enough performance for any sims coming down the line in the next 8-12 months. Then you could upgrade to Pentium II or whatever when they're NOT at their peak price.
Sincerely,
Shui-Che Lim
Letter 3: from Dan
I've been reading the posts on your page and you seem to be vastly underestimating the relevance of FPU performance.
As scenes become more and more complex, FPU performace becomes more and more important. First of all, a game engine gets its speed not by drawing triangles fast, but by deciding which triangles don't need to be drawn. This almost always involves fully transforming the triangle and doing some sort of acceptance test on it before shipping it off to the 3D hardware. Of course, all these computations are done by the FPU. The more complex the scene (i.e., more triangles) the higher the percentage of triangles that has to be rejected before being sent to the 3D unit.
Second, many game engines will be tesselating on the fly, meaning that the surface patch models (or whatever) will be turned into triangles as each frame is rendered. This is unlike the current technique where several frames of animation are pre-tesselated and the proper model is selected for rendering. All of the new animation techniques that you hear are going to be used in Trinity, Prey, et. al. are extremely FPU intensive.
You also seem to be confusing triangle setup with geometric transformation. They aren't the same thing. Triangle setup is the generation of the iterative parameters that are used by the rasterizing engine. This has no relation at all to geometric transformation, which is very CPU intensive. A good programmer can do triangle setup in fixed point - not even using the FPU. No currently shipping consumer level (under $1000) 3D card does geometric transformation in hardware. I've not even seen one announced.
The point you make about Direct3D not knowing how to use the VooDoo 2's triangle setup is also incorrect. D3D hands whole triangles (or even strips or fans) to the D3D driver supplied by the OEM, in this case the VooDoo 2 reference drivers written by 3Dfx. 3Dfx's reference drivers then decide how to perform setup.
The price difference between a PII/233 and a K6/233 is about $100 on the street. For OEM's, it's more like $50. A more appropriate comparison is between the K6 and the Pentium MMX, where the price difference is $50 on the street and about $25 for OEM's (233 MHz). That money will about double your frame rate in Quake (with a 3Dfx card, triple it for unaccelerated hardware).
By the way, I've had a Cyrix 200+ and a Pentium 120. Even with the 3Dfx card, the Cyrix (at 512x384) could not beat the Quake frame rates of the P120 (at 320x240). Dan
Dan,
I try not to underestimate the importance of the FPU, but try to temper my judgement with the consideration of the genre that I'm specifically writing about. Games such as Quake/QuakeII, Daikatana, SiN, etc. due to the nature of the genre are vastly triangle limited. If this is your cup of tea, then you'd be well and right to say that Pentium II would be the best solution.
However, please keep in mind that the focus of Combat Simulations is on... well, combat sims. Simulations generally don't have the scenery or object complexity of your first person action shooters. Quake/QuakeII can easily generate two times (or more) the number of polygons to render per scene than most current combat sims such as Longbow 2 and F-22: ADF. This suggests to me that simulations are less triangle limited and more fill-rate limited. While this may not be the case for all sims and may not be the case for newer sims currently in development, it does seem to apply to the sims that are available now.
If there is any truth to the above statement, then you'd realize that my recommendation of a good Socket 7 CPU with dual Voodoo2's vs. a Pentium II-300 with a single Voodoo2 may not be out of line. You would most certainly end up spending far less money on upgrading your Socket 7 CPU and going with two Voodoo2's than you would for the Pentium II-300 setup. However, for fill-rate limited sims, you might also reasonably expect comparable or even better performance.
On whether Direct3D actually supports hardware triangle setup, I've got too many different answers to be able to say for certain. But what is certain (at least according to the benchmarks on Tom's Hardware for Turok), is that D3D triangle support for Voodoo2 is rather lackluster compared to native Glide support. This is especially important since sims will generally ship with Glide support out of the box.
Even for triangle limited games like Turok, the Pentium II-300 with a single Voodoo2 showed only 30% better framerate than and AMD-K6/233 or Pentium 200MMX with Voodoo2. I'll assure you the price difference is certainly more than 30%. And while you make a good point about using lower speed Pentium II's such as the 233, there are no benchmarks to compare performance against the K6/233 or Pentium 200MMX - it would be safe to say, however, that there would be less than 30% better framerate.
Given these points, I will still stand by my opinion that a dual Voodoo2 setup under a good Socket 7 CPU is just fine (and could possibly be preferable) for combat simulations. The best part of this strategy is that you can still upgrade to faster CPUs as newer sims demand, but it won't cost you an arm and a leg to do it since you're no longer using the CPU to ride the performance curve.
Sincerely,
Shui-Che Lim
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