some questions about WRAM

[chhfchhf]

WRAM is a kind of ram on the video card board.
it is very similar with SGRAM.
could some one tell me the difference between them?
thanks!

[FormerEx-SalesSoup]

Re: some questions about WRAM

Originally posted by chhfchhf
WRAM is a kind of ram on the video card board.
it is very similar with SGRAM.
could some one tell me the difference between them?
thanks!

Thanks to Webopedia.com:

Windows RAM, is a type of memory that is dual-ported. This enables a video adapter to fetch the contents of memory for display at the same time that new bytes are being pumped into memory.

SGRAM is single-ported. However, it can open two memory pages at once, which simulates the dual-port nature of other video RAM technologies. In addition, SGRAM uses several other techniques, such as masked writes and block writes, to increase bandwidth for graphics-intensive functions.

[rylan]

Yeah, SGRAM (Synchronous Graphics RAM) is basically like your normal DRAM structure, but has some additional features such as block and page moves that made it a little better for frame buffers.

WRAM (Window RAM) is dual ported (seperate read/write ports) as mentioned, and uses a serialized type interface to output data. Because of this it has a high internal bandwidth, but was also more expensive and not uses as much due to needing a specialized controler instead of a standard DRAM type memory controler.

[Haig]

Also,

The first port, the random read/write port, worked like a plain old DRAM (not SDR, not DDR, not EDO). This is the port that the graphic engine uses to draw.

The second port is an output port only which is used to drive the Ramdacs to do display refreshes. The read/write port is 32-bit, and the output port is 16-bit.

Haig

[FormerEx-SalesSoup]

Originally posted by Haig
Also,

The first port, the random read/write port, worked like a plain old DRAM (not SDR, not DDR, not EDO). This is the port that the graphic engine uses to draw.

The second port is an output port only which is used to drive the Ramdacs to do display refreshes. The read/write port is 32-bit, and the output port is 16-bit.

Haig

thanks for one-upping me.

[Ribbit]

Everything that has been said about WRAM - the dual ports, one ordinary read-write, one serial output-only - are features of VRAM (V for Video). There's nothing WRAM specific there. VRAM was popular around the same time as the Vesa Local Bus, since DRAMs of the time did not have the bandwidth to feed a high-speed RAMDAC and satisfy a graphics controller.

Here's where I get a little hazy, and therefore untrustworthy; the feature of WRAM was its ability to perform some graphics operations by itself. Probably mainly operations like bitblts. This would save a great deal of bandwidth between the memory and graphics controller, as well as make the bitblt operations a lot faster. This would explain the Millennium's fast Windows performance, and also why the Millennium II was faster under Windows than even the G200.

Corrections/clarifications welcome.

[FormerEx-SalesSoup]

Originally posted by Ribbit
Everything that has been said about WRAM - the dual ports, one ordinary read-write, one serial output-only - are features of VRAM (V for Video). There's nothing WRAM specific there. VRAM was popular around the same time as the Vesa Local Bus, since DRAMs of the time did not have the bandwidth to feed a high-speed RAMDAC and satisfy a graphics controller.

Here's where I get a little hazy, and therefore untrustworthy; the feature of WRAM was its ability to perform some graphics operations by itself. Probably mainly operations like bitblts. This would save a great deal of bandwidth between the memory and graphics controller, as well as make the bitblt operations a lot faster. This would explain the Millennium's fast Windows performance, and also why the Millennium II was faster under Windows than even the G200.

Corrections/clarifications welcome.

Window RAM or WRAM is a modification of regular VRAM that both improves performance and reduces cost on a bit-for-bit basis. Designed specifically for use in graphics cards, WRAM is also dual-ported but has about 25% more bandwidth than VRAM, and also incorporates additional features to allow for higher performance memory transfers for commonly used graphical operations such as text drawing and block fills. Furthermore, WRAM is less expensive than VRAM to manufacture (although still more expensive than DRAM).

again, from Webopedia.com

[Pace]

Is this a competition to see just how comprehensive an answer we can give?

[rylan]

Also if anyone is wondering, you can't get WRAM anymore, its been end-of-lifed for several years now. SGRAM is EOL also, but there was a lot more of it made, so you can still find places with stocks of it. Oh yeah, same is true for VRAM :P

[GNEP]

But there is plenty of SPrAM around. They sell it in tins.

[Haig]

"Is this a competition to see just how comprehensive an answer we can give?"

Nah, I'm just re-phrasing what Soupy is trying to say.

What Soupy is trying to say is that the major differences between Wram and Vram are the Vram read/write port are 16 bit where as the Wram is 32bit. Access time for Vram is 100ns and 60ns for Wram. Vram has no block write where as Wram has 2-color.

Apart from that, the WRAM supports a 2 color blot write operation (better for characters),where as VRAM supports only 1 color block write.

The WRAM can support internal blit-blits, but the restrictions about
what you could do were to severe for anyone to use.

[DukeP]

Lol.
I cant help but to love these discussions. They are just SOOO MURCS.


~~DukeP~~

[FormerEx-SalesSoup]

Originally posted by Haig
"Is this a competition to see just how comprehensive an answer we can give?"

Nah, I'm just re-phrasing what Soupy is trying to say.

What Soupy is trying to say is that the major differences between Wram and Vram are the Vram read/write port are 16 bit where as the Wram is 32bit. Access time for Vram is 100ns and 60ns for Wram. Vram has no block write where as Wram has 2-color.

Apart from that, the WRAM supports a 2 color blot write operation (better for characters),where as VRAM supports only 1 color block write.

The WRAM can support internal blit-blits, but the restrictions about
what you could do were to severe for anyone to use.

rephrase at will...i just copied and pasted anyway. thanks, H.

[WayneHu]

Originally posted by rylan
Also if anyone is wondering, you can't get WRAM anymore, its been end-of-lifed for several years now. SGRAM is EOL also, but there was a lot more of it made, so you can still find places with stocks of it. Oh yeah, same is true for VRAM :P

I believe Samsung was the only manufacturer to produce WRAM. That was the disadvantage for the price competition. The similar thing happens to RDRAM, again...

No matter what kind of RAM type the current GPU uses, it does not seem to catch up with the required bandwidth of GPU's 3D calculation under very high resolution or complex rendering.

[rylan]

Yup, from what I saw at work only Samsung made WRAM. We had some old cards that used it, so we still have a stock of the stuff for repairs. lol