neXGam

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spart natürlich kosten, was mich eignetlich wundert weil die kyro2 (also der pc ableger von dem grafikchip) wurde schon sehr heiß also müssten die hier schon was getrickst haben um die kühl zu halten.

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probiers halt bei deinem pc, du kannst den fsb und die cpu geschwindigkeit hochdrehen aber das ändern überhaupt nix an der grafikkarten taktfrequenz.

wenn du die cpu hochtaktest dann ändert sich einwenig was am fsb (bis zum nächsten teilerschritt wird der fsb und die damit zusammenhängende busse mhz mässig erhöht) aber es ändert sich nichts an anderen takten (zB grafikchip, soundchip usw) nur die daten kommen schneller dort an.

dH das zB beim pc der pci bus dann nichtmehr mit 66 mhz läuft sondern mit 68-70 usw usw bis man eben zum nächsten teiler schritt kommt, daher ist es auch möglich mit 133-166-200 fsb zu arbeiten - hier sind einfach teiler die das die mhz so teilen das sie wieder auf ca 66 mhz kommen (das gleiche beim agp und pci-e usw)

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Original von krobi

ich stell nicht in frage ob es was bringt, ich bin sogar sicher dass das übertakten der cpu was bringt - nur müsste man viel mehr rausbekommen wenn man den grafikchip übertaktet (dieser hat wie jeder andere chip auch seinen eigenen unabhängigen takt).

zur kühlung
müsste es nicht reichen in den boden ein loch reinzumachen und einen schönen großen 120iger lüfter dran festzumachen? währ viel leiser als solch ein kleiner lüfter und man könnte die dc sicherlich weiters hochtakten (zB den grafikchip).
HIER[/URL]

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Das Übertakten der GPU soll möglich sein und auch was bringen, nur
soll es dann angeblich nur noch möglich sein die Dreamcast an einem
VGA-Gerät zu betreiben da die Signalfrequenzen für normale Fernseher
dann nicht mehr stimmig sind.

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Well, I just got a reply from someone at that site who definately seems to know his stuff. Get this, that GPU line? Thats NOT a GPU line. The the motherboard FSB line. So when we overclock the GPU, we are actually overclocking the RAM and everything else. Here is the reply.

"This is not entirely correct. The basic clock signal comes from a 13.5MHz
oscillator that is fed to a PLL that indeed generates a 54MHz and a
33.33MHz signal. The 33.33MHz signal is fed to the SH4 which generates a
200MHz signal that is used internally, but it also generates a 100MHz
clock that is fed to the rest of the system, including the Holly chip
(which includes the graphics core but also lots of bus control logic) and
SDRAM. That 54MHz from the PLL is indeed also fed to Holly, perhaps it is
even used internally by the graphics system, I'm not sure; the main stuff
would be running off the 100MHz clock though. The primary use of this
clock seems to be to as a pixel clock for the video encoder.

You state that you want to overclock the SH4 to 300MHz, by I'm guessing,
feeding it a 50MHz clock instead of 33MHz. You think the problem is the
1.8V. Sorry, I can't help with that at the moment, but I'm thinking there
are lots of other problems too, such as clocking the GPU and main/video
RAM at 150MHz instead of 100MHz..."

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Oh crap. I totally misinterpreted that. Get ready for long ass post, strted off by my reply to what he said X.X

"> VERY interesting. I had no idea the so-called "GPU" pin was actually
> the FSB pin. I appreciate the information. So what your saying, is
> that to make overclocking the CPU more possible, I would also possibly
> have to raise the FSB so that the CPU doesn't go out of sync?

I think you have misunderstood what I wrote. Forget about that 54MHz "GPU"
pin for a moment. Here's a simplified clock diagram (use fixed width
font to view properly):

.-------. .---------------.
| Xtal | | SH4 |
| 13.5M | .---+--+---x6-CORE | .------------.
`---+--' | | | 200M | | SDRAM |
| | | | | 100M | Main mem. |
.---+------. | | `---x3-------+---+---------+ 100MHz |
| PLL | | | 100M | | | |
| 54M 33M | | `---------------' |100M `------------'
`--+----+--' | .-------------------+------. .------------.
| | | | Holly | | | SDRAM |
| `----' | (System ASIC) .--+---. | | Video mem. |
`-------------+---. | `-+--+ 100MHz |
| | .-------+----. | | |
| /n | PowerVR | | `------------'
| | | 100MHz | |
| | `------------' |
`---+----------------------'
|13.5M/27M
.---+---.
| Video |
| DAC |
`-------'

As you can see, the 33MHz clock is multiplied by 6 inside the SH4 to
generate its core operating frequency of 200MHz. It is also multiplied by
3 to generate a 100MHz clock that in your terminology might be called the
"FSB" clock.

This "FSB" clock is used to drive the SDRAM and most stuff in Holly
(including the GPU). Since the 100MHz is generated by multiplying the
33MHz clock by 3, if you change the input to 50MHz to get a 300MHz CPU
clock, the "FSB" clock will be half of that ie 150MHz instead!

Listen to what Simon said: the GPU limit might well be 133MHz (and since
he designed the damn chip, you might want to consider he knows what he's
talking about!). If the GPU is running at 133MHz, the SH4 will be running
at twice that, namely 266MHz, which is close to the limit you state:
270MHz. So it seems quite probable to me that it's not the SH4 that is
the limiting factor. It very well could be the GPU!

Returning to that 54MHz "GPU" clock now. As you can see it is not really a
"GPU" clock at all; it is more properly termed "pixel clock" since it is
used to drive the video encoder/DAC. The 54MHz pixel clock is not
multiplied by 2 (as I've seen asserted); it is actually divided by a
divisor n that is controlled by bit 23 in hardware register a05f8044:

bit 23
------
0: n = 4 (pixel clock=13.5MHz NTSC/PAL mode)
1: n = 2 (pixel clock=27MHz VGA mode)

So overclocking this clock will do little to increase the GPU speed. It
will only screw up the refresh rates so the signal is no longer NTSC/PAL
compatible

> But yeah, still looking for the 1.8v thing-a-ma-doo-dad.

I'm **GUESSING** that IC104 **MIGHT** be the one to generate the 1.8V. It's a
five-pin 1.5-7V variable voltage regulator that you'll find it on the
flip side of the PCB, near the SH4 but further towards the edge. I would
not recommend you to attempt anything drastic without being sure you know
what you're doing, and if anything goes wrong, don't blame me!"

So in fact, the GPU/FSB pin only controls the pixel clock, not either the GPU nor the FSB. The *CPU* pin controls EVERYTHING.

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Original von DC-One
Wie ist denn der Kühlkörper mit dem Innenleben verbunden?

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Original von doccybrown
Ich sage nur 'passiv' =D
/doccy