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turok_t

Different 7800GTX in SLI

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I currently have the XFX 7800GTX 256MB. It is preclocked to 490Mhz core already in the box and I have oc'd it even more to 525Mhz.

 

A) Can i use another 7800GTX that is NOT by XFX in SLI?

 

B) If i get a second 7800GTX (regardless of the brand), will my oc'd speed (525) or the prevlock speed (490) be dragged lower or affected in any way?

 

Thanks for all your help

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The way it was explained to me by BFG, was if the cards have identical specs they will work, but if one variable in its core is differant, it will not. A card sold as overclocked will not work with a card that all stock. a "GTX" will not work with a "GTX OC" The next ? you have to ask yourself, is how comfortable are you that the listed spec you see, is correct. Comfortable enough to risk a restocking fee if its not? IMO i would want to test a card before i bought it, barring that, get an identical one.

 

I learned all this when i built my system, and only bought one card. When i went back to get another, it was discontinued. I called BFG directly to find out my options, but a member of this forum found my matched card for sale on the internet by another vendor. So i got my matched set anyway. But BFG had already told me i could just get there newer/repackaged GTX or anyones 7800GTX that had identical specs.

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So the cards have to be EXACTLY the same with the SAME core frequency? Do the new nvidia drivers that just came out allow mixed vending? my XFX 7800GTX 490Mhz core will be really hard to find in the future.

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As far as I know they need be the same make-model(Core-mem mhz's) with the same device bios flashed to them. (so the bios versions match) I just ordered a 7900gt and inna' few months.(June) I hope to sli a seconed. But I expect I'll have to flash the first cards bios to match the seconed.(But it could work outta' the box.) Hope that helps some."Clay"

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Well, I have mixed cards in my rig, and no they dont have to be the same brand, but they do have to be the same gpu...7800gtx with another 7800gtx...for you id suggest another brand that has that 490Mhz core and 1300Mhz (I think???) memory. Getting a card with lower clocks will simply force your card down to the lower one's specs. As far as flashing bios for the cards, I never had to do a thing...mine are both clocked at 450/1250 and it works flawlessly. Nvidia 8x.xx drivers allows you to do all of this. I advise you just to find a 7800gtx with your cards speed to get the best results...any brand, mine are XFX and Leadtek, works like a charm and very awesome boost.

 

EDIT: btw, you should bring your clock speeds back down to stock before adding that second card. After you set it up and enable SLi, then go and overclock again if desired

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I currently have the XFX 7800GTX 256MB. It is preclocked to 490Mhz core already in the box and I have oc'd it even more to 525Mhz.

 

A) Can i use another 7800GTX that is NOT by XFX in SLI?

 

B) If i get a second 7800GTX (regardless of the brand), will my oc'd speed (525) or the prevlock speed (490) be dragged lower or affected in any way?

 

Thanks for all your help

 

I would buy the card from the same specs/brand just to be safe... that way you know that they are clocked at the same speeds...

 

As far as OC'ing, when running 2 cards you won't be able to OC as much as running a single card... with a single card I was able to OC it stable pass 600/1800, when running SLi I can't get them to go 5mhz over the OCed stock (580/1750) without getting arctifacts...lol

 

Hope this helps.

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hey guys,

 

thanks for all your replies, ideas and suggestions. So i guess most of u suggest that i get another 7800gtx 256mb with a core of 490Mhz. I totally agree. I have heard from many instances that running in SLI sometimes lowers the performance in games. Why is this? Secondly, and most important, is it really worth $600 (im in canada and the 490mhz core cost this much) to buy another 7800GTX?

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hey guys,

 

thanks for all your replies, ideas and suggestions. So i guess most of u suggest that i get another 7800gtx 256mb with a core of 490Mhz. I totally agree. I have heard from many instances that running in SLI sometimes lowers the performance in games. Why is this? Secondly, and most important, is it really worth $600 (im in canada and the 490mhz core cost this much) to buy another 7800GTX?

 

Haha, cant say it is worth it seeing that they are way overpriced as of now. I got my second card at such a great discount from my cousin that I jumped at the chance. You should not be paying more than $350 US dollars for a 7800 gtx... do the canadian conversion and find out what the price is. I got my 2nd card for $250...used but I know its flawless since it is my cousin. And I say its overpriced because one, it is a one year old card now and two, the 7900gt is out for $300-$350 and its a bit faster than the 7800 gtx. It costs nVidia more to make a 7800gtx hence the still high price. If you're willing to, eBay or even the "for sale" threads here or at anandtech.com might be a good place to pick up a 7800 gtx from those who have upgraded and need to drop it off. ORRR, you can pick up a 7900gt and sell your 7800gtx for probably the price you bought the 7900gt and then pick up another 7900gt...lots of hassle, but it is an option.

 

As far as loss of performance, it should be quite the opposite...you should see your frames go up at least 15fps with max settings and all at 1600x1200 or whatever you play at. You should be able to increase your AA and AF more too...I was pretty stoked with the boost I got for sure and my cards are still at stock. I play Oblivion at 4xAA 8xAF with bloom at 1600x1200 and its absolutely beautiful. May overclock later when needed.

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Ya thanks for the reply. I was considering those options- buying 7900GT and selling 7800GTX..... the price for a 7800GTX is waay overpriced and i dont want to buy another one of those....Either way, i know i would be loosing $$$$. Oh yeah, one more thing, i have a OCZ PowerStream 520W. Is that enough for SLI?

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Ya thanks for the reply. I was considering those options- buying 7900GT and selling 7800GTX..... the price for a 7800GTX is waay overpriced and i dont want to buy another one of those....Either way, i know i would be loosing $$$$. Oh yeah, one more thing, i have a OCZ PowerStream 520W. Is that enough for SLI?

 

Oh yea, that'll be enough, mine is overkill, but then again it was a gift :nod:

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hey guys,

 

I have heard from many instances that running in SLI sometimes lowers the performance in games. Why is this?

 

No i cant say i agree with that statement one bit. Second card mainly adds framerates with stability. They just dont drop under load like a single card. Its a max out every game kinda situation. No more tweaking game ini's for a few more fps, you just dont need em.

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