GPU Upgrade: A Tale

By St1ckM4n · 27 replies
Mar 12, 2013
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  1. As some of you may know, I recently purchased a new HD7970 card to replace my GTX295. Herein lies the aftermath of this decision.

    I'm having morning tea at work and I receive a package. Excitedly, I open it up expecting something great - tadaaa! My Sapphire HD7970 has arrived! :D I am excited for when I can get home and swap it out in my PC.

    Once at home, I hurriedly open up the package, revealing the GPU sitting in a bubble-wrap antistatic bag. Clever. I flip it around and I notice a big STOP sticker on it, so I take a closer look.

    At this stage I'm having something to eat, so I'm casually reading it, just because there's nothing else to do. I knew I'd need to connect the card to my PSU - nothing new here. I look closer at the specs... 1x4-pin "lolwtf, would that run?".. 2x8-pin???? I finish my food, open up the bag, and lo and behold there are x2 8-pin PSU connectors on the card. What. The. Hell.

    This throws me back. I don't think I've seen a GPU in recent days that's reference-spec with x2 8-pins.. only the ARES and the like have had these I thought. I panic slightly as I go to my computer to open it up and take a look at my current connectors. I should be fine, GTX295 was a beast back in the day. Well, I better be fine, because my other PSU connectors are 200km away. I open up my case and I'm immediately let down - 6+8pin. Damn.

    Slightly more panicked, I hop on the web to check out why the hell my card has two 8-pins. I look through a few reviews - all of them have 6+8 pin. The manufacturer website pictures show this too. Lol I must have a secret prototype. Defeated and none the wiser, I decide to deal with the PSU pins later.

    I proceed to take out the existing card out of my CM Storm Scout case. I really like this case, with the carry handle and all, and the not-so-overly-big size. Mid-towers are neat. I plop the GTX295 on the bed next to the 7970 to 'compare sizes'.

    Lolwut. The 7970 is big. Unexpectedly big. I am taken aback at the sheer girth of this thing. Ok I'll stop now. I pause, as I remember that my GTX295 barely fit into my case to begin with. To be honest, I didn't even consider the size - 295 was a behemoth and from review articles I got the thought that current-gen cards are smaller. Plus, 7970 is single-GPU... I check my case, double-check with the old card inserted. Yup, the 7970 is too big. Too big by exactly the red rectangle.

    I inspect the card - it's got the plastic shroud on it, angled in a funny way. I guess it looks cool. But what a stupid retarded decision, to make it stick out so much. I look at the back - it's just plastic, all the cables and screws stop at the boundary of the PCB. Haha, it would actually be pretty easy to just use a hacksaw and get rid of this extra bit.

    Hacksaw and get rid of..
    Knife to get rid of...

    I have a serrated kitchen knife. This is the closest thing I have to a saw at this moment. Being the utter genius I am, I decide to give the knife a shot. I put the card on the kitchen bench, line up with the knife and start cutting. Five minutes later, it hits me: I have a $400 brand new component on my kitchen bench, with a kitchen knife in it. I don't even know if the card works at this stage - it could be DOA! The warranty is probably void at this point. Incoming paperweight...?


    Whatever. Too late to back out now. I risk it and keep cutting. 20 minutes later, I get tired of this - it's really really hard work. I look around the house and I have no other tools to help me out. Realising I have a small tiny pair of pliers at work, I drive over and pick them up (it's 20 mins return, easy). I come back to the card, looking at it, look at pliers. Back at card. This is a big risk. If I use pliers to try and pry a piece of plastic off, the whole shroud could shatter, leaving one or both fans useless. Whatever man, I'm out of warranty anyway, too late for this. I tentatively grip a piece of plastic at the top that had a decent cut in it. With the smoothest of possible actions, I lever it away from the card.

    It's bending. WHAT. The plastic is actually bending. I realise it's one of those plastics, where it's almost as if it hasn't set fully yet. It's bendable and pretty much shears off, instead of snapping into little pieces. This method is so damn easy, that I take five minutes to omnomnom the side of the shroud into a crude line. Whatever, I don't care about sharp edges, this'll do.

    I shove the card into my case. Well, by shove, I mean 'place in my case with the utmost care in order to not damage my other expensive components'. Looking at the totally forgotten x2 8-pin connectors, I give up and just connect the existing 6+8pin. After all this effort, you'll boot up, card, or I'll destroy your soul. I make sure everything is plugged in, whack cover door back on, connect the power. It boots.

    The rest of the story is nothing special. I installed the drivers, everything went smoothly. The card idles at 31C, which is the coolest component in my case. Under load it's 54C, which is the point at which my GTX295 idled. It's quiet at load - 35% fan speed. An excellent card. But, whats the story with the x2 8-pin connectors?

    tl;dr: herpty derpty shmurp, check your card length guys.
    fimbles, Jad Chaar, Dawn1113 and 4 others like this.
  2. LinkedKube

    LinkedKube TechSpot Project Baby Posts: 3,486   +45

    Lmao at that knife.
  3. MrBlkfx1

    MrBlkfx1 TS Evangelist Posts: 863   +204

    My 7950's are just as big lol. I compared them to my old 6950's and they looked massive. Funny thing, the 7950's came in a box at least half the size of the 6950's.
    Darth Shiv likes this.
  4. Benny26

    Benny26 TechSpot Paladin Posts: 1,535   +51

    Wow what a story, not sure I'd have had the guts to take a knife to it like that. I'm probably the type of guy who would suffer forking out cash for a new case, even if it was for an extra inch or two.

    Glad it came through in the end though.
  5. Darth Shiv

    Darth Shiv TS Evangelist Posts: 1,811   +472

    Yeah bought a Sapphire HD7950 OC thinking "Geez this old HD4870 OC is ludicrously massive and loud. The HD7950 OC is quiet and quiet means less heatsink right?" Wrong :confused:

    Damn card was almost an inch longer. Had to angle/recess the card into a hard drive bay then into the PCIe slot to get it into the case! Only needs 2x6 pin but my PSU came with 2x8 pin cables.
    MrBlkfx1 likes this.
  6. LNCPapa

    LNCPapa TS Special Forces Posts: 4,276   +461

    OMFG. I can't believe you did that St1ck. That was just plain nuts... but I'm glad it all worked out for you. I spent the last couple of minutes laughing and wondering if you'd end this story with "I'm just kidding guys".
    mosu likes this.
  7. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 3,448   +145

    Right that seemed a bit rash. I think there are better options than going under the knife!
    Technically the 8 pin just has two extra pins that are used as ground so... I think it works if you just short them. You also seem to have it working without doing anything except knifing the case.
  8. St1ckM4n

    St1ckM4n TS Evangelist Topic Starter Posts: 2,922   +630

    Haha, I'm glad you were all entertained. :D

    To reiterate, I was only hacking into the plastic shroud. There's the PCB, then there's the heatsink and fins on top, then the black shroud on top of this. There is no functional use to the part that I hacked off.

    As for the PSU plugs, my question still stands - why are these x2 8-pin? No review of the card, nor manufacturer website lists it as such. Are there any benefits..? I plugged in my 6-pin cable and left the left-most two pins (from angle of photo) empty.

    I'll put a pic below of the PSU plugs, compared to my GTX295. The red bit is what I removed.

    And here is the finished product. :D
  9. MrBlkfx1

    MrBlkfx1 TS Evangelist Posts: 863   +204

    It kinda looks like it was chewed off lol. Either way, at least you got it to fit.
  10. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 3,448   +145

    Well as I said the 8 pin basically just has two extra ground pins, which means that there's slightly less resistance but that's about it AFAIK.
    Now why it's there I haven't a clue :)
  11. St1ckM4n

    St1ckM4n TS Evangelist Topic Starter Posts: 2,922   +630

    Hence my inclusion of "omnomnom" in my story. :p

    Ok cool, thanks.
  12. misor

    misor TS Evangelist Posts: 1,285   +243

    So the op is a stickman and the knife used to cut the plastic edge is his sig? :)
    btw, I envy your courage to do that cutting.
  13. LukeDJ

    LukeDJ TS Maniac Posts: 350   +112

    Wow. That's the ballsiest thing I've seen someone do to a PC component, and a $400 one at that! Glad it worked out for you man :p
  14. slh28

    slh28 TechSpot Paladin Posts: 1,706   +172

    Lol loved the story. If I were you though, I would have just bought a new mid range case and PSU with 2x8 pin connectors considering they would only cost around half of what you spent on the GPU and could be used in future builds...

    My 7970's both have 8+6 pins but then again they are both reference cards. It's not uncommon to see OC cards with 2x8 pins.
  15. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 3,448   +145

    Although the outside looks different, the Vapor-X version does have two 8 pins, so maybe they put the wrong PCB in O.O.
  16. cliffordcooley

    cliffordcooley TS Guardian Fighter Posts: 9,739   +3,706

    6-pin or 8-pin, it's not a question of how much power the cable can provide. It's more a question of how well the system can sustain a proper ground under a heavy load.

    Adding additional ground will reduce the resistance within the grounding wires. This also reduces the voltage loss within the wires themselves, by strengthening the ground within the card. If you have a weak ground, strong loads can raise the voltage of the ground (this is also known as floating a ground if it is not anchored to earths ground) and play havoc on the electronics in which they are supplying power. It's the floating effect that you are minimizing, by strengthening the ground.
    misor likes this.
  17. St1ckM4n

    St1ckM4n TS Evangelist Topic Starter Posts: 2,922   +630

    While a good idea, my build is using an i7 920 with aftermarket heatsink and it's all cable-tidied etc. This thing can last me another year or two at least. The effort of transferring everything over to a new case, along with the massive cost (I need to post, postage on cases is huge due to weight) wouldn't make sense. Also the PSU is modular, so I just need to grab my other cables. :p

    cliffordcooley: A nice explanation. Thanks.

    Yeah, it's pretty weird. The bundle is different to other mentioned stuff on their site (perhaps regional) and it's actually missing software on the CD that the box says it has.
  18. Darth Shiv

    Darth Shiv TS Evangelist Posts: 1,811   +472

    6 pin are rated 75W. 8 pin are rated 150W. I'd say 6 pin would get "warm" if run over rating at a guess?

    Source: Sapphire HD7970 specs
  19. cliffordcooley

    cliffordcooley TS Guardian Fighter Posts: 9,739   +3,706

    Which doubles the current flow across the same three wires. It's grounding that is enhanced not the ability to deliver power. The 6-pin will also deliver 150W's but needs a stronger ground to remain within spec. Specs which were made to ensure the cards functionality. With that said; there is no guarantee the card will not function unless it is within specifications. It is always best to stay within spec though, as the specs were made for reasons.

    Another thing to consider is when a 6-pin and 8-pin are used in combination, the two additional grounds from the 8-pin also aid the 6-pin. Current is split equally across all six power sources, and all grounds are shared. This means there will not be any more of a strain on the 6-pin connector than there are on the 8-pin connector (and vis-versa).
    dividebyzero and misor like this.
  20. dividebyzero

    dividebyzero trainee n00b Posts: 4,891   +1,264

    Shouldn't be too much of an issue. St1ckM4n has at least one of the 8-pin PCI-E connected as such (He would have had to for the GTX 295)
    1 x 8-pin = 150w
    1 x 6-pin = 75w
    PCIe x16 slot = nominal 75w (although a draw of 90w or more isn't uncommon on a lot of boards).

    PowerTune limits the 7970 to ~250w, and even taking a torture test transient peak before PT applies itself won't allow the card to reach 300w ( TPU measured 273w transient under Furmark for a GHz Edition card)
  21. St1ckM4n

    St1ckM4n TS Evangelist Topic Starter Posts: 2,922   +630

    That same specs site says I need 1x 6-pin 75W. Later down the list (not sure why) it says I need 1x 8-pin 150W. Nowhere does it say I need x2 8-pin, which is why I'm still confused.
  22. cliffordcooley

    cliffordcooley TS Guardian Fighter Posts: 9,739   +3,706

    Lets rearrange the specifications a bit and see if it is easier to comprehend. Looks to me they are saying 1x6-pin and 1x8-pin. Unless you are going with Crossfire, then 2x6-pin and 2x8-pin would be needed.

    You can use 6-pin power in a 8-pin connector, the connectors are keyed so they will only go one way.
  23. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 3,448   +145

    Yes I think they are saying one 6 pin and one 8 pin but instead it has two 8 pins.

    If it works it works though :cool:
  24. Dawn1113

    Dawn1113 TS Booster Posts: 322   +65

    This made me do a double-take. Heh-heh. This would never have crossed my mind -- I am far from daring when it comes to these things. Anyways, good job, St1ckM4n! Whew! I wonder, though, what the "amputated" plastic appendage was for? Apparently, it was there just for aesthetic reasons?

    PS: Cool photo of that chef's knife cutting into the GPU, too! I just love that one.
  25. St1ckM4n

    St1ckM4n TS Evangelist Topic Starter Posts: 2,922   +630

    Yeah, aesthetic only. It wasn't 'scooping' the air. The attached pic shows location of fan header cable and screws which joined the plastic to the heatsink.

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