Haig Help! G450 DualBus confusion.

[cjolley]

Haig (or anybody who knows)
Wutzup with the G450 & DualBus
Here is an exchange I had with Glide Underground about the switch to DDRRam.
Could you clarify?
thanks,
chuck
---------------------------------------------
Thank you for your concern, but we've checked up with Matrox's PR system on this and what we've written is actually accurate. They read over the whole thing and said all the details were fine, so the preview we've written is accurate until one of the guys at Matrox says otherwise. Thank you for your consideration and we'll keep up to date on the G450 issue. Enjoy our website and we'll try to keep on bringing the best information to you and all our readers.

Thank you,
Chris Kim (internet alias: Stories)
------------------------------------
Glide Underground
(www.glideunderground.com)
"Massively Updated Gaming News!"
------------------------------------
Software Division Manager
chris@glideunderground.com
Phone: (303) 693-1852
ICQ UIN: 7740719
AOL IM: Stories83
----- Original Message -----
From: cjolley
To: News@GlideUnderground.com
Sent: Wednesday, May 24, 2000 4:19 AM
Subject: Matrox G450 Preview Mistake DualBus


Hi guys
re: the Matrox G450 Preview
You have now joined the masses of reviewers to confuse the switch from
32 bit SGRam to 64 bit DDRRam with a shrinkage of the 2x128 bit
DualBus.
All they did was switch Ram types, the memory bus is still 2x 128 bit
pipes.
Chuck

"..., will benefit from the chip’s 256-bit DualBus architecture. "
Straight out of the press release.

---------------------------------------------



------------------
ABit BF6, P3-650@910, 128mb gh@140cas3, 10gb IBM@7200, SB Live Value@3.0, Pioneer 104s DVD, Mitsumi CDRW@2x2x8, Acatel 1000 ADSL@1.5mb/sec, Linksys EtherFast NIC, LG 995e, USB IntelliEye,Matrox G400 MAX!!!!

[Stringy]

what the Reviewer at Glide underground messed up was the fact that the DualBus, is the INTERNAL bus structure, inside the chip and not the ext. memory bus.....

On reg. G400 the EXT. Mem. Bus is just 128Bits wide,
on the G450 the Ext. Mem. Bus is 64Bits...

The G450 as far as I've read still has the 256Dualbus internal structure...

Craig

[Maggi]

Hi guys,

here's some input for you:

Normal 128 bit RAM (well actually 4 chips of paralleled 32 bit SGRAM) works as follows:

Every time the memory clock would go from 0-1, all 128 bits of data
would get stored, then pushed. That is to say, 1x128bit transfer per clockcycle.

clock data
0 IDLE
1 transfer 128 bits
0 IDLE

With 64 bit FCRAM (DDR) it is twice as fast and basically transfers on both edges (per clock cycle), so you
could cut the bus in half, and still get the same perfomance:

clock data
0 IDLE
1 transfer upper 64 bits
0 transfer lower 64 bits

The end result on both cases is the same. In one clock cycle 128 bits of data are transfered.

The advantage is space, and cost. The chip package would become much smaller
because you could drop 64 pins.

The 256 bits (internal) DualBus is not affected by this changed memory design, as it would still deal with 128 bits per clock cycle coming from the RAM as it did before.

...

Feel better now ?



Cheers,
Maggi

[Mark F]

The BIG advantage of the new 64bit memory, is that to get 32MB they only need 4 chips rather than the curent 8. And in the long run that with the curent 4 chips per side design they can get 64MB

Mark F.

------------------
OH NO, my retractable cup holder swallowed a DVD...
and burped out a movie




[This message has been edited by Mark F (edited 25 May 2000).]

[halfblood]

I feel better anyway.
Thanks for the explantion.

[franksch3]

I still believe the memory interface will be 128 bits. The G400 uses some 32 bit SDRAM chips in parallel to make a 128 bit memory interface.

On the G450 they will use 64 bit DDR-SDRAM chips in parallel to still make a 128 bit memory interface.

In their official release they have stated that their external memory bus is 128 bit. That is the real bus width and says nothing about the speed of the memory itself.

No SDRAM chips at present have a 128 bit bus because it is to expensive. Thats why every card uses some SDRAM chips in parallel to create that 128 bit bus.

They now use 64 bit DDR-SDRAM to decrease the number of chips used, but in parallel.

[Salmonius]

I think that the goal of the g450 is to be an inexpensive good card. The memory thoughput will probably be the same and there are no significant additions relating to speed to the core.

Any speed improvement would come from the chip and memory running on a faster clock. It's going to be a cheap card to produce with half the memory chips and everything else integrated on the g450 chip. So basically it's going to be a g400 running at a faster speed that fits in the palm of the hand and that costs (presumably) a little less than the original g400.

Because of my limited patience, I might get a v5500 if I think the price is not too much (saving up for a miata). But other than that, I'd be happy to get one.

[Livius]

Yes but do not forget that with the 400MAX we had a 128bit interface to SGRAM running at 200MHz, while now we will have a 64bit interface to SDRAM/SGRAM running at 300/333 MHz. I think that in purely abstract terms were talking about better memory management with the G400MAX all things considered (but not with the G400, that is if Matrox will use 166/333MHz DDR on the G450).

[This message has been edited by Livius (edited 26 May 2000).]

[cjolley]

I think the point then becomes..
If they can produce a souped up G400 at the price of a V3-2000 (or less), they will sell a lot of cards.
chuck

Which brings up a question - what happens to the PC market it the OEM grade PCs have better visuals than the high end PCs?