SLI question

By crushem1
Jul 4, 2013
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  1. I have a GeForce GTX 660 Ti FTW+ 3GB and I want to add a second card.
    My question is do I need to buy a second card that has the same amount of ram or can I buy a 2GB and save $50 bucks since it doesnt use that ram anyway

    I have an 800w power supply so that shouldnt be an issue.
  2. GhostRyder

    GhostRyder TechSpot Evangelist Posts: 2,160   +506

    You need to match the cards most of the time, however on ram differences, from what I understand it will just limit the total amount of ram accessible to the lowest amount (In your case 2gb will be useable on both cards). That is at least how it works on the GTX 680 4gb versions if you mix a 2gb together.

    I would recommend getting a matching pair, it causes (Or has the chance to cause) more issues then just putting a twin right next to it.
  3. crushem1

    crushem1 Newcomer, in training Topic Starter

    Thanks for the answer.
    Ill just spend the extra 50 and have peace of mind.
  4. cliffordcooley

    cliffordcooley TechSpot Paladin Posts: 5,806   +1,431

    If I read this correctly, it is how I understand it as well.

    The way dividebyzero explained SLI/CFX to me is the card with the least amount of memory is the one that sets the bar. Data is duplicated across both cards. One card will process the even bits (ignoring the odd bits) of memory and the other card will process the odd bits (ignoring the even bits). A 2GB and 3GB SLI combination will result in 2GB total usable memory.
  5. LinkedKube

    LinkedKube TechSpot Project Baby Posts: 4,265   +41

    He was correct. Both cards will only use the amount that accessible on the 2gb version.
  6. JC713

    JC713 TechSpot Evangelist Posts: 6,797   +882

    I think it is worth the extra $50 because you may want to run at a higher resolution than you are currently running at.
  7. St1ckM4n

    St1ckM4n TechSpot Evangelist Posts: 3,428   +618

    Tbh it could even be worthwhile trying to sell your current card and getting a whole new one... depends on price, of course.
  8. JC713

    JC713 TechSpot Evangelist Posts: 6,797   +882

    Make sure you case has enough ventilation also.
  9. crushem1

    crushem1 Newcomer, in training Topic Starter

    Thanks for the replies.....I just bought the same card to eliminate any hassles.
    I have 6 fans and liquid cooling so heat isnt an issue...so far
  10. JC713

    JC713 TechSpot Evangelist Posts: 6,797   +882

    Good to hear. Best of luck!
  11. LNCPapa

    LNCPapa TS Special Forces Posts: 4,284   +262


    Wise move. This way you get to take advantage of the 3GB of VRAM.
     


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