Thanks, I´ve fixed it.
RSX architecture and cost...
- Thread starter SOcean2forever
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Thanks, I´ve fixed it.
inefficient
Veteran
In gaming PCs the GPUs are on add on boards. Overeclocking that one part is not going to pose a risk to the whole system.
On the PS3 the RSX is right there on the same board in the middle of a forest of other expensive components.
I would like to add that yield takes into consideration the quality of the chip - it's not just about reaching those clock speeds, but reaching them at an acceptable power (static/active power consumption of the transistors) and hence heat output.
Recall that G71 was only introduced around Spring 2006. Sony needed hundreds of thousands of them by the end of that year- a much bigger scale production than normal and for a new chip (nVidia got rid of 30M transistors or so compared to G70). The easiest way to increase the usable number of chips to fit within TDP set by Sony would be to decrease the clockspeed.
Getting that last 50MHz might have knocked out a fair number of chips for launch supply; heat/power scale non-linearly.
Still, in the end it comes down to the manufacturing spec which only Sony can supply.
BTW frying only the graphics card is a bummer as well. Some cards automatically throttle down the speed if they are over-heating, the PS3 probably has similar functionality. I don´t think over-heating is a big risk on the PS3 given all folding@home clients that are chugging 24/7 under all kinds of conditions all around the world. And honestly, how much extra heat we are talking here: 3, 5, 10, 20 W?
the thing is that the geometry and the textures are still covering the same area of screen space for the same frame at any resolution (difference is how many pixels are in that area). So if 1 texture block of 2x2 texels is necessarily read to fill, say, 5 pixels at 720p, then that same block will be read to fill 10 or 11 pixels at 1080p. If that block is still in the texture cache when you get around to various pixels among that 10 or 11 pixels, you haven't issued more reads from RAM than you would have otherwise.
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GT7900GTX: G71 @ 650 MHz + 512 MB GDDR3 @ 800 MHz generates 84.2 - 89 W
GT7900GT: G71 @ 450 MHz + 256 MB GDDR3 @ 660 MHz generates 48.4 - 64 W
A 50 MHz difference would probably generate less than 8 W (and that would also include a possible down clock of the PS3 GDDR3 RAM from 700 to 650 MHz as well and still I have not taken into account that the RAM is 50% smaller on the GT7900 card. Maybe the extra heat would be closer to 5 W in reality.
archangelmorph
Veteran
Actually we're not allowed to do that..
The problem is that you can't gaurentee an old PS3 can be overclocked to 550 MHz. Those PC card software allow small variations, and you push your GPU as much as you want to until it fails (software failure, not hardware). If you have a spec for a 550 MHz GPU in PS3, and then leave users to overclock the GPU on old PS3's, ignoring the situation of requiring techno-chumps to mess about with overclocking, there are no guarantees that 550 MHz can be reached. You'd need access to voltage lines and repeated attempts of reboot/tweak/test/reboot until you could find a clockspeed that works. Then you'd have the fans potentially whizzing up (don't know how much extra heat would be produced) and users would worry about their machine, even if it was safe.
If Sony could roll out a software update to achieve this, it would be on the design decision to enable this before the hardware was released, like PSPs 333 MHz system that was clocked to 2/3rds. At which point, why did they clock at 500 MHz? On the PSP the decision was for battery life, but in the hardware all they need worry about is heat and yields. The system could cope with omre heat with more fan speed...
A retro-fit solution isn't viable. You can't expect millions of Joe Public owners to be able to run an overclocking tool with repeated power offs/ons (you could automate some of it through a log file) to end up with a clock speed that offers no obvious improvements. At the end of the day I think most people would regard a clock change as too much faff. The best chance of overclocking would be (if the hardware can even support it!) as an option for 'hardcore' users to get more FPS out of titles if they choose to, like offering Linux as an option that very few owners will bother with. But I don't see Sony going for that somehow...
If not the RSX being bumped to 550MHz, could the clock rate for the memory be adjusted to 700MHz from 650MHz. This would provide 22.4 GB/s towards GDDR bandwidth rather than the 20 GB/s being achieved on the 650MHz.
Initially, games were developed very simply, hardly any optimisation for UMD use, and no real effort in changing the clock of the PSP's CPU to the exact level that is needed for every aspect.
But the PSP is designed to run at any mhz up to 333. If I understand it correctly, you can set its clock at any time to anything from 1 to 333 and every 1mhz step inbetween. So if you only have to display a graphical menu with hardly any animation (or none) and you're just waiting for button presses, you can get away with close to 1mhz. Some Homebrew reader software also took advantage of this feature (as of course did the tools that allowed homebrewable PSP owners to run a lot of existing games at 333 already in the early days of the PSP).
We are also getting more games running off memory stick.
The extra memory is I think partly intended for caching (this was always announced I think), but it's something that the developers aren't allowed to control themselves. The PSP's OS will perform some caching itself, which has the advantage that the regular 32MB PSP remains the reliable baseline against which developers need to work, where 64MB PSPs can be anything from performing equal to noticeably faster.
To get back to the PS3 however, I don't see the point of 500 vs 550. Difference seems insignificant.
It´s no longer because the issue was forgotten(?) among the horde of Internet nerds that attacked the PSP because they couldn´t use it for more than X hours a day. The numbers of different scenarios i have seen described where only a DS could work was amazing.
With 2.5 hours of gaming pr day it would have been more than enough. One charge pr night no problem. But it seemed that many guys had no problem playing 4 hours plus outside their house everyday. Crossing the country every 2nd day, and flying non stop to other countries etc etc.
I never cared for battery life anyway.
I obviously expressed it in a bad way, I never meant PC-style overclocking. If and only if the hardware was designed for a higher clockspeed, the frequency bump would probably be controlled by a switch in an API made available in some future SDK release. i.e. it would be controlled by the developer PSP style but with less range and maybe just two steps.
I am not betting any money on that this will happen, but since a lot of reserved memory has gradually been made available on both the PS3 and the PSP and that higher fequencies have been made available on the PSP, I am neither betting any money on that the GPU + VRAM frequency of the PS3 has been set in stone by Sony.
I guess we will know for sure within 3-4 years from now. :smile:
Thanks Arwin for the clarification of how the extra DRAM is used as a cache in the new PSP.
Back in the days when I pushed my graphics cards, a 10 % increase was clearly visible.Arwin said:
Panajev2001a
Veteran
If you know the size and features of the cache (best case latency, replacement policy, the worst case scenario for a miss in that cache, etc...) then you can optimize your data access for that and make your game run a lot better when it is run on a PSP Slim.
My old PSP can freeze during game if clocked at 333 MHz.
The RSX is house in that platter with its memory chips like a laptop configuration. I don't know why they don't spread the memory like the Cell chip.
Anyway, I reckon 50 MHz will go along way. Games like Lair see framerate improvement when played on NTSC, so it will see benefit for OCing the core and memory of RSX even only by 50 MHz.
It would be nice if consoles come with an OC utility for both CPU and GPU and memory. Maybe Extreme Edition consoles ?
Betanumerical
Veteran
does RSX run @500 MHZ
Has it been confirmed that the RSX was under clocked to 500 from 550? I have been hearing that for a long time now but I have never seen that confirmed. In fact I remeber a thread about a month ago here on Beyond3d about RSX and Linux that was speculating about people being able confirm clock speak and all sorts of other facts about RSX that are protected by NDA once Linux got full access to the RSX.
Has it been confirmed that the RSX was under clocked to 500 from 550? I have been hearing that for a long time now but I have never seen that confirmed. In fact I remeber a thread about a month ago here on Beyond3d about RSX and Linux that was speculating about people being able confirm clock speak and all sorts of other facts about RSX that are protected by NDA once Linux got full access to the RSX.
Panajev2001a
Veteran
) ? Is the game running at 333 MHz due to homebrew enabled overclocking ?The RSX and associated memory will never get that 50Mhz boost; if all the chips in these consoles were capable of that level of operation either a) period, or b) within certain voltage and thermal envelopes, they would never have been released at their present speeds to begin with. So, immediately it's obviated that some PS3's, even if the clocks could be adjusted through firmware or on an app basis, would fail to operate at those frequencies. Thus, Sony would never do it.
The situation is different for the PSP, where all chips are nominally rated to achieve 333Mhz; the decision to pull back on that was purely due to power draw and thermal concerns, rather than a seeming yield concern within a certain spec.
The situation is different for the PSP, where all chips are nominally rated to achieve 333Mhz; the decision to pull back on that was purely due to power draw and thermal concerns, rather than a seeming yield concern within a certain spec.
Do you know that the RSX is not nominally rated to achieve 550 MHz?
We know that GDDR3 DRAM is rated to achieve 700 MHz.
and here you can decode the VRAM circuits.
I can understand your logic that if the circuits were capable of higher speed they should be running at that speed right out of the gate. But I have seen some convoluted logic motivating different decisions before, so I don´t take anything for granted.
If it was just the RSX that got down-clocked from the original spec it would have been easier for me to accept your logic, but what makes me dubious is the fact that the VRAM is downclocked almost proportionally. Sony/Nvidia fucked up the design pretty badly if the memory speed was so hardly coupled to the GPU so they have to run the memory 50 MHz below its nominal spec. As we know the RSX would greatly benefit from some additional bandwidth that is pretty bad IMO. For some reason I hold the skill of Sonys engineers higher than that.
Whatever, you may be right, nevertheless I will still keep an open mind to the possibility.
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