Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Guiyon

macrumors 6502a
Mar 19, 2008
771
4
Cambridge, MA
Thank you. I ordered a couple of the AT25DF041A-SSH(H|HF)-B chips (50MHz and 70MHz variants) from DigiKey to test out along with a sample request from SST for the SST25LF020A-33-4C-SAE. Once I get these in (and pickup a card) I'll report back my success.
 

MacVidCards

Suspended
Original poster
Nov 17, 2008
6,096
1,056
Hollywood, CA
Rom,Rom, Rom... I usually trust you, but this is totally wrong. You are correct that it's a 64k part...at least a 64kByte part. When it says 64k x 8 it is specifing that it's 64k by 8 bits wide. NOT 8 pages of 64k each.

If you take the 64k and multiply by 8 bits you get 512kbits. Flash and ram parts are useally specified (these days anyway) by their bit capacity, not their byte capacity.

I sugggest you have a ;look at the data sheet: http://pdf1.alldatasheet.com/datasheet-pdf/view/153931/PMC/PM25LV512.html

You'll see this part is specified as a 512kbit part organized as 64kBytes.

hyram

This is an instance of me not knowing the "why" but knowing "what works"

All of the chips with 512 in their name have been 64K chips. This was a problem back when the Radeon 9800 was king and we were fighting the 64K vs 128K battle.

Thank you for the technical details, though I have to admit I still don't know what exactly your explanation means.

I just know that is a 64K chip and attempts to flash it with anything more than 64K will result in a BRICKED CARD that will likel require an actual PC with alternate Video Out to fix.

I am very concerned that this thread will result in bricked cards RMA'd to the same retailers I use. That is why this flash should only be attempted by people with enough skill and knowledge to read the part numbers, solder chips, and fix their mistakes.

I will also NOT be posting the EFI ROM for this card. It is not mine to post and I have no desire to test EVGA's Litigation Attorneys. There is also the ethical issue of "biting the hand that feeds".

If someone else is unencumbered by these concerns, they can post it wherever they wish.
 

hyram

macrumors regular
Jun 15, 2009
190
0
This is an instance of me not knowing the "why" but knowing "what works"

All of the chips with 512 in their name have been 64K chips. This was a problem back when the Radeon 9800 was king and we were fighting the 64K vs 128K battle.

Thank you for the technical details, though I have to admit I still don't know what exactly your explanation means.

I just know that is a 64K chip....

My apologies.. I get a little anal retentive about technical matters. I always want to be as accurate and precise as possible. And I could have been a little more clear. I'm going to blame a lack of Mt. Dew.

Memory structures can come in numerous configurations: the most common being 8 bit wide, 16 bit wide, and 32 bit wide "words"; and have ever increasing densities: 256 kbits, 512 kbits, 1024 kbits, etc. Memory parts are specified by this bit density, not by the word density. For example: a 512 kbit part can be 64k of 8 bit words, or 32k of 16 bit words, or even 16k of 32 bit words.... It all comes down to how the manufacture wants to configure their part internally. This is usually reflected in the part number somehow.

What set me off in your original explanation was that you stated:

It would seem that there are 8 pages of 64K each but for whatever reason, when these chips are used as EEPROMs for GPU, they only access the "first page"

This would imply that these parts have 512k words (64k times 8) internally which they do not... they have 512 kbits configured as 64k worth of 8 bit words. I know... refer to the part above where I mention "anal retentive".:rolleyes:

On a side note: These memory parts generally have what is called a "page mode" of access. Where you send a "read (or write) page" command and the part will return an entire page worth of data which can vary in size again depending on how the manufacture wants to make the part. This is usually only possible with serial flash parts which the devices you're using here are. The particular part called out here has 256 word pages, so when you do a page read you get 256 words back. For parallel flash parts there's another meaning for "page" but we won't get into that here.

I hope this explanation is a bit clearer,

hyram

PS: I've specifically avoided the usage of the word "byte" as sometimes it can add more confusion that it resolves.
 

Frixo Cool

macrumors regular
Jun 10, 2004
120
25
Croatia
Now, when the dust has settled, is there any proven info are there PC cards out there with large enough EPROMs? Is there any PC GTX285 I can buy and to be pretty sure that I can flash it to Mac and use dual-DVI with Cinema 30"?

Thank you very much! :)
 

vailance

macrumors member
Nov 29, 2008
34
0
MY
i think its none of the pc card out there have 256k of rom size. you have to solder yourself thats what they are doing. :)
 

MacVidCards

Suspended
Original poster
Nov 17, 2008
6,096
1,056
Hollywood, CA
Now, when the dust has settled, is there any proven info are there PC cards out there with large enough EPROMs? Is there any PC GTX285 I can buy and to be pretty sure that I can flash it to Mac and use dual-DVI with Cinema 30"?

Thank you very much! :)

This thread contains the sum total of what is known regarding flashing these. So, so far we have found 2 with 64K chips and one with a 128K chip. Not promising, but it is possible that there are cards out there with 256K chips.

Meanwhile, I am still open to making a SECOND flashed GTX285 for someone who brings their 3,1 or 4,1 Mac Pro and a 1 Gig EVGA card over. I have a 2 Gig version I need to test........
 

vailance

macrumors member
Nov 29, 2008
34
0
MY
@The Rominator

Can you let us know where else can i get a 256k compatible rom size ? and maybe a picture of the part where u soldered the rom chip? i might want to try on that. Got an Gtx285 today. :) Thanks!
 

MacVidCards

Suspended
Original poster
Nov 17, 2008
6,096
1,056
Hollywood, CA
If you are new to surface mount soldering, this REALLY isn't the place to pick up experience.

I didn't take a pic of the chip, but I can tell you that you need to remove 14 screws to get Fan off. Once you remove it, the chip is on upper edge of card on front face, quite near the SLi connectors.

First you should run "Nvflash -c" and it will give you the part number. The chip will have this part number on it too, this way you can be sure you are removing right chip. Removing old chip is tricky part, if you pull up a trace from PCB you will potentially have KILLED this lovely new card. I want nothing to do with responsibility for that.

Mouser & Digikey carry small electronics in US. DOn't know about elsewhere.
 

vailance

macrumors member
Nov 29, 2008
34
0
MY
will this works for 285? - Macronix-MXIC-MX25L2005-2M-BIT-SPI-Flash-BIOS
http://cgi.ebay.com/1-x-Macronix-MX...0?hash=item5ad12e4fe3&_trksid=p3286.m20.l1116

3ab3_1.JPG


below is a sample of whre the chip located, its just below the sli connectors
55562912.jpg


How can i make sure i didnt solder it upside down?
 

22Hertz

macrumors regular
Oct 20, 2007
116
0
Like Guiyon said, desolder the chip, align the dot on the corner of the chip to the dot on the board (Pin 1) and solder.

Use lots of flux and minimal solder.

Let us know how it turns out for you
 

MacVidCards

Suspended
Original poster
Nov 17, 2008
6,096
1,056
Hollywood, CA
The "Dot" is on both PCB and the chip.

And it is always bst to do a hi-res scn of card BEFORE removing chip. Gives you a reference in case anything goes wrong.

I usually just go by whatever way the writing was "rightside up", sometimes it is easier to see than the dots.

The suspense is killing me.......
 

10THzMac

macrumors 6502
Dec 17, 2007
376
0
If you are new to surface mount soldering, this REALLY isn't the place to pick up experience.

This is a really intimidating thread for those of us who have never even picked up ANY kind of a soldering iron. I feel much better now there are questions like "How can I make sure I didn't solder it upside down"?

Rominator - have you thought about what issues might be involved in sorting out a 295 - given the 2xGPU and memory config do you think that will have a totally different ROM?
 

bozz2006

macrumors 68030
Aug 24, 2007
2,530
0
Minnesota
If you've never soldered before, you might be better off shelling out a case of Miller Lite to your friend who knows how to solder. Make sure not to give him the beer until after he's done, he'll need steady hands for this little job.
 

MacVidCards

Suspended
Original poster
Nov 17, 2008
6,096
1,056
Hollywood, CA
This is a really intimidating thread for those of us who have never even picked up ANY kind of a soldering iron. I feel much better now there are questions like "How can I make sure I didn't solder it upside down"?

Rominator - have you thought about what issues might be involved in sorting out a 295 - given the 2xGPU and memory config do you think that will have a totally different ROM?

I stand by my statement that people with little or no soldering experience should NOT undertake EEPROM swapping. If you absolutely insist, try it out first on some old piece of hardware that is useless. These are $300+ cards.....and one lifted trace can be like dropping 15 @ $20 bills into a campfire.

If you can reliably do it on some old GeForce 2, then go for it. (There are other chips that use SOIC8 packaging, move a few around and see how they look) But if your attempts on said GeForce 2 look like a recreation of The Battle for Berlin, then HAVE A PRO DO IT! Nothing will ruin your day better than knowing you PERSONALLY wasted a brand new card.

As far as GTX295, I expect it will be like the 9800GX2. You can run a GX2 with Netkas package and additional Nvidia card, but it sees it as 2 @ 9800 cards. So, Netkas package either will now or will in future enable this card, but it will likely be seen as 2 @ GTX285s and full power only in WIndows.

I like the beer idea. So I will make a standing offer.......anyone who wants this done can bring me a GTX285 and a 6 of Stella, I'll switch chips. Hollywood & Highland area. (extra points if you bring your Mac Pro)
 

TheLostBrain

macrumors newbie
Jul 2, 2009
4
0
Any reason to do this mod on a hackintosh?

What's up guys. I just bought the EVGA FTW version of this card :D but I'm running OSX86/Hackintosh. Is there any benefit at all to me doing this mod as opposed to just using an injector, etc.?

Thanks. :)
 

netkas

macrumors 65816
Oct 2, 2007
1,198
394
What's up guys. I just bought the EVGA FTW version of this card :D but I'm running OSX86/Hackintosh. Is there any benefit at all to me doing this mod as opposed to just using an injector, etc.?

Thanks. :)

you nickname explains all.
 

vailance

macrumors member
Nov 29, 2008
34
0
MY
yeah agree i have some slight skill on soldering wires on psu unit but not something small like the chip, i can solder no prob but i think wouldnt take the risk. I'll just send to some handphone repair shop and ask them do for me. :D will report back with my success story..
 

TheLostBrain

macrumors newbie
Jul 2, 2009
4
0
Well thx ...

you nickname explains all.

Heh, well I guess your saying there's no point. However would it possibly help to prevent compatability issues such as going to and resuming from sleep etc? Also wouldn't I need the mac rom for the 5.0 vs 2.5 gt /s ?
 

netkas

macrumors 65816
Oct 2, 2007
1,198
394
Heh, well I guess your saying there's no point. However would it possibly help to prevent compatability issues such as going to and resuming from sleep etc? Also wouldn't I need the mac rom for the 5.0 vs 2.5 gt /s ?

why would you need efi part of rom on pc without efi itself ?
 

MacVidCards

Suspended
Original poster
Nov 17, 2008
6,096
1,056
Hollywood, CA
ie...there is no part of PC that loads EFI part of ROM, even on a Hackintosh, so there is no mechanism to benefit from EFI on card
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.