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Yeah, the part about it pulling 106 FPS when the 3d renderer is taken out of the equation definitely points to it not being the CPU limiting the overall framerate.  Since the G5 has a world-class bus speed and 8X AGP, I doubt we're seeing much bottlenecking there.  It's when OpenGL kicks in and has to do its thing do we see the performance plummet.  The game's renderer can probably be optimized somewhat, and the rest is up to Apple, improving their OpenGL drivers and such.  Many of the OpenGL extensions and such being used by DOOM 3 are newly implemented in Apple's OpenGL, though, so there's probably a lot of room for improvement and optimization for these newer features.  Tiger's close, so that's something to look forward to.

Still, a timedemo doesn't tell the whole story, for Macs or for PCs.  I played around with DOOM 3 on my friend's brand-new Dell (3.4 GHz P4, 1 gig RAM, GeForce 6800) a few weeks ago, and while the timedemo delivered nice numbers in the 60-70 range at 800x600, there was a fair amount of noticeable stuttering during gameplay, and when he brought up the counter it hovered mostly in the 30-40 range, and dipped into the 20's whenever there was 4-5 or more enemies on screen or lots of stuff bouncing/falling for the physics to calculate.  It was a surprising disparity between the timedemo and actual gameplay.  I don't know if this is the case on other systems, since I've only played it on this new Dell and my other friends' Athlon, which is dragged down by his crappy GeForce 4 MX, so the framerate is rather poor at any resolution or quality level.

30fps ought to be enough for anybody.  Nobody complains about video being jerky or having rough motion. Film is only 24fps.  Pulling twice that on a game that renders like Doom3 will be fine. This game is probably the first game for the Mac that renders in a way that is closet to a real ray traced 3D scene, so I think it should be fine on any G5 system with a good GPU.

I think some of you need to understand that Doom3 looks so realistic that you don't need the massive frame rates. Other games look "fake"... and I personally feel that the high fps rates help on games that do not look real. 

-mark

Last edited by avkills (2005-03-03 7:07 pm)

avkills wrote:

30fps ought to be enough for anybody.  Nobody complains about video being jerky or having rough motion. Film is only 24fps.

One critical difference, tho- motion blur. Each frame in a game is rendered very crisply, like a photo that is very sharply focused and with a very high shutter speed- game screens can capture extremely brief events. Film and video, of course, do have motion blur to help appear smooth. 

Pulling twice that on a game that renders like Doom3 will be fine. This game is probably the first game for the Mac that renders in a way that is closet to a real ray traced 3D scene, so I think it should be fine on any G5 system with a good GPU.

I think some of you need to understand that Doom3 looks so realistic that you don't need the massive frame rates. Other games look "fake"... and I personally feel that the high fps rates help on games that do not look real. 

-mark

In my experience, it always helps to get a framerate boost, up to the 60-75 range. Above that it's all smooth to me (not to say anything less is unlivable).

I'd be interested in that analysis.

Something is screwy, but I haven't figured out what. The G5 seems to have a fine architecture, but so far its games performance hasn't matched. The D3 engine is sound, I've been thru the comments in different forums; but something's still amiss. AnandTech is pretty telling on this, and these are fairly recent... the first link is on resolution scaling (D3 in red), the second on different cards' 1600x1200 performance (the Mac X800 XT should come in just below the PC's):

http://www.anandtech.com/video/showdoc. … 90&p=3

http://www.anandtech.com/video/showdoc. … 0&p=10

Lightning Fast, and CPU Bound
The high performance of cards like the Radeon X850 XT Platinum Edition dictate that, even on today's fastest CPUs, they will be CPU bound at resolutions lower than 1600 x 1200. To prove this we've taken three GPU limited benchmarks, Half Life 2, Doom 3 and Far Cry, and showed their performance scaling vs. resolution using the X850 XT PE on an Athlon 64 4000+:

Puzzling. Time will hopefully tell. (Btw, the A64 4000+ runs at 2.4GHz).

Actually the 60fps cap could make a lot of sense, and here is why.  NTSC video refreshes at 60Hz, however, since there are only 30 frames per second, something must be amiss.  All is fine.  Each video frame is made up of 2 fields.  When they first designed TVs, they could not get the phosphors to glow long enough, so they split the frame into two fields, drawing one field and then the next every 1/60th of a second. Since computers monitors are progressive, it would actually make sense to keep the fps rate at or near 60fps to match the vertical refresh as dj phat 2000 pointed out.  LCDs really don't have a vertical refresh rate just pixel response time.  LCDs refresh the entire screen at once.  I imagine the vertical refresh for a LCD just changes how many times a second it attempts to refresh all the pixels.

As far as motion blur goes, that is a cop out in video terms.  Shooting at very high shudder speeds with film or video yields footage with little to no motion blur.  In the movie Gladiator, fight sequences in the arena were shot this way.  That is what made the images are so crisp and the movement of the weapons are sharp as well as dust, etc etc.

However, having motion blur would make a game more realistic.  The game Lugaru has this, but it seems to take it overboard IMO, although it is pretty cool.

I believe somewhere I read that one of the main reasons PCs continue to outperform Macs is that the way the software and the system sends data to the GPU is quite a bit different. Maybe Apple has addressed this in Tiger and we will all be pleasantly surprised.

-mark

avkills wrote:

Actually the 60fps cap could make a lot of sense, and here is why.  NTSC video refreshes at 60Hz, however, since there are only 30 frames per second, something must be amiss.  All is fine.  Each video frame is made up of 2 fields.  When they first designed TVs, they could not get the phosphors to glow long enough, so they split the frame into two fields, drawing one field and then the next every 1/60th of a second. Since computers monitors are progressive, it would actually make sense to keep the fps rate at or near 60fps to match the vertical refresh as dj phat 2000 pointed out.  LCDs really don't have a vertical refresh rate just pixel response time.  LCDs refresh the entire screen at once.  I imagine the vertical refresh for a LCD just changes how many times a second it attempts to refresh all the pixels.

LCDs don't have a refresh rate per se. They change brightness and color values at a certain speed (response time) as the signal sent to them varies.

Anyway, most CRT monitors aren't set to refresh at 60Hz. OSHA sets 72 as a minimum for the workplace. Most computer users set to 75 or higher. Citing the refresh rate of (interlaced NTSC) TV doesn't seem relevant.

As far as motion blur goes, that is a cop out in video terms.  Shooting at very high shudder speeds with film or video yields footage with little to no motion blur.  In the movie Gladiator, fight sequences in the arena were shot this way.  That is what made the images are so crisp and the movement of the weapons are sharp as well as dust, etc etc.

Very little footage in either medium is shot that way, tho, and if tightly focused, high-shutter-speed film were displayed at the lower, rapidly varying framerates of many games on many systems, the results would be dismaying to many. (Yes, framerates can vary greatly with extreme rapidity, as shown by a few games with graphical framerate displays).

However, having motion blur would make a game more realistic.  The game Lugaru has this, but it seems to take it overboard IMO, although it is pretty cool.

Realistic, or more like movies?

I believe somewhere I read that one of the main reasons PCs continue to outperform Macs is that the way the software and the system sends data to the GPU is quite a bit different. Maybe Apple has addressed this in Tiger and we will all be pleasantly surprised.

-mark

That's awfully vague... Macs send data by smoke signal perhaps? That'd be rather wasteful of all that G5 FSB speed...

Someone, I believe Glenda Adams, posted at IMG to not expect too much of Tiger. More like incremental gains going forward.

Is that anything like beer goggles?

Twisted Guy wrote:

Inter-frame motion blur.  That's what we need to make things look realistic, fluid, and movie-like.

Inter-frame motion blur.

Yes, but that is what happens in video because it captures movement between fields. I don't know about anyone else, but I wish NTSC video would die and go away. Field rendering animations and motion graphics takes almost twice as long as rendering them progressive. Film is progressive, but most likely blurs due to the 24fps capture.

Actually, PCs usually beat out G5s in 3D apps when you talk OpenGL preview speeds. Rendering speeds are pretty much on target though.

Maybe Apple has some low-level bullsmurf running between the GPU and the OS. I don't see where it would be a "unix" problem, since Linux x86 computers don't seem to have the same problem.

-mark

Bat wrote:

Very little footage in either medium is shot that way, tho, and if tightly focused, high-shutter-speed film were displayed at the lower, rapidly varying framerates of many games on many systems, the results would be dismaying to many. (Yes, framerates can vary greatly with extreme rapidity, as shown by a few games with graphical framerate displays).

Someone, I believe Glenda Adams, posted at IMG to not expect too much of Tiger. More like incremental gains going forward.

Yes I agree that watching film or video and having the fps jump all around would be very bad.  And you would be surprised on how much stuff is shot with a high speed shutter. For really clean slow motion, you usually need to shoot with high shutter speeds.

I seriously doubt Tiger is going offer much until developers tap into the new features of core video.

What Apple needs to do is re-write their entire OpenGL library in Assembly.

-mark

What would that do for performance on the Mac?  And if it helps that much.  WTF Apple snap to it! 

Writing it in Assembly that is.

Last edited by dj phat 2000 (2005-03-04 9:10 am)

the Battle Cat wrote:

No, it was written in Visual Basic for a reason!

I knew there was something amiss....   Actually some of it probably is Assembly, but I bet the majority is some flavor of C.

-mark

Last edited by avkills (2005-03-04 9:54 am)

Jehannum wrote:

During the C code compilation process (and, pretty much any compilation process), the code goes through a preprocessor and assembler to spit out... assembly code.

The compilers available do a far more consistent job of optimizing code for the destination architecture than people do.

The speed of assembly code vs. compiled C is vastly overestimated on modern platforms.

Yes I know that.  However, someone who has their smurf together could code better than the compiler.  After All, humans make the compiler, so there is a good chance that the compiler will not do everything "the best way".  I am not knocking the compilers or the people who write them.  And I understand the importance of people understanding your code which is probably the main reason not to code to Assembly directly.

-mark

Actually, I have to reassess your Hero programmer scenario to "unlikely", in the face of this project. 

Over large projects, compilers invariably win out, because they do data flow analysis (a simple accounting program for a computer, a hoary bear of a problem for a human, who is probably using spreadsheets for such a task). 

Additionally, the compiler is way more willing to generate un-maintainable assembly output that a human would never consider.