Question for developers... PS3 and framerate

Jobboy, did you listen music from your HDD, or some Mp3 player, or downloading stuff when you notice framerate drops?
Got you the last frimware?

 

two things to quickly check:

- same resolution was used?
- there were some issues I recall if you forced your bluray output to 24hz apparently

 

If it's on a the singular same game it can be a problem a duplication of the game… but in this case it's more a streaming problem (lake of texture, etc…) but with use of the HDD may be it's translate in some framerate drop?

 

actually, from experience, 720p runs better than sdtv resolutions. my guess is that all games render at that res and downscale accoardingly (though from what i've seen no aa is added)....

 

I agree, a lot of games do that (and at least you get some additional supersampling on your SDTV )

 

Cell has 8 spu's and if during manufacturing 1 of the 8 spu's is found out to be broken chip can still be used to build ps3. For PS3 there is no difference in performance if there is actually 7 or 8 working spu's. The eight spu is never used for anything but redundancy to make the chip cheaper to manufacture.

As for spu broken in use how the hell could single spu become suddenly defective while rest of the chip continues to function properly? In theory I guess it could be possible but in reality that is something that really just wouldn't happen or be reasonable to implement.

 

I'm not a developer, but my guess would be the PS3 wouldn't boot at all if it's power on system tests fail. That or if it escapes the system test, your game will just randomly crash as the defective SPU starts giving rubbish data.

 

I have cod 4 for the 360 and there are in fact frame rate drops when there are some explosions...its not exclusive to the PS3.

 

Have you checked that you and your friends have similar setups? Do you have a Widescreen TV and your friends have normal 4:3 TVs (this affects camera fov and thus performance)? Do you use different resolutions (1080i/1080p, 720p/720i, 480p/480i)? Interlaced screen also usually looks a bit more laggy than progressive, and different TV-technologies produce different amount of perceived lag (overhead projectors are usually pretty bad for any games that require lightning fast reflexes). Also check that you are using correct cable to connect your console to your TV. If you have different options, it might be a good thing to test them all (for both performance and image quality improvements).

 

Or simple his more sensible for framerates drop than his friends…

 

The 8th SPE is physically disabled I believe. But even if it were just left there, I am under the impression that there is a task/job queue and the work is sent out to the SPEs as they become available to do a job.

Developers will tailor the tasks with having 7 SPE's in mind, but there is always the possibility that the 7 SPEs are in use at a given time slice with more jobs on the list where an 8th SPE (or more) would allow that next task to be started. Of course, the speed increase may not even be noteworthy if one of the original 7 SPE's was just about to finish a job anyway.

http://research.scea.com/research/html/CellGDC05/34.html
http://research.scea.com/research/html/CellGDC05/38.html

 

The 8th SPU is disabled during manufacturing and you cannot gain access to it through the firmware or OS..

 

I don't think they intentionally disable it, after all they do still need "fully working" CELL chips for some of it's other applications (Medical, Army etc.etc.)

I guess it's possible that the yields have improved so they now have to disable one during manufacturing, but I haven't heard as such from anyone.

 

Seems that it's cheaper to produce a chip with 8 SPUs on it and switch off one if it's faulty, rather than produce a 7 SPU chip and if any are faulty then you have to scrap the whole chip and make a new one.
I guess it's a bit like how a manufacturer makes a 3 GHz CPU but sells it as 2.6 GHz, just to be safe.. (but at least in a PC CPU you can try overclock it through jumpers or software)

 

Ah, thank you. Then let my previous post be expanded to a hypothetical chip with 8+ working SPEs.

OT, but had to comment -->

With the layout as is, there is nothing lost by producing the image of the 8th SPE onto the wafer. If you did leave out the imaging of the 8th SPE, you'd just have a big blank area on the die (the dice would be the same size).

The chemical etchings still take the same amount of time as they're applied to the entire wafer at the same time. The exposure... may take slightly longer having to do the 8th SPE, but the gains of having it there for redundancy and yield far outweigh the throughput time. A redesign with only 7 SPEs to make a rectangular die would just be odd (forgive the pun) anyway, and not worth Sony's time.