870m and the 680m

All I know is the 870m is slightly more powerfull but does it also produce more heat and which has more overclockable room, the 870m or 680m? Or is the 870m already a overclocked 680m?

 

I think there was a thread on here recently discussing these two cards and I believe the verdict was the 870m beats 680m if both are stock but 680m beats 870m when overclocked with a unlocked vbios. I would assume the 870m is more power efficient based on it being newer tech but I could be wrong.

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The 870m is a gimped 680m however the core and mem are clocked quite high

The gimp comes from the mem bandwidth

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I would still say 680m is a better card due larger memory bandwidth that always helps in higher resolutions. Both cards overclock fine though, and yes performance is similar.

 

At 1080p it's a fair match unless you're willing to clock the heck out of the 680m, which probably means a significant over voltage as well.

 

The other way round, as the 870m has 120GB bandwidth and the 680m 115.2GB.

 

I thought the 870m had fast ram?

 

With current clocks, yes.
However 680m has larger memory interface, 192 bit vs 256 bit.
If you overclock then 680m will definitely have much higher memory bandwidth then 870m.
At current clocks 870m is faster however if you overclock then i believe 680m has higher potential because of larger memory interface

 

Just get the 880M QED

 

Or the 870m if you can't stretch for the 880m and be done with it.

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As far as I remember, the 680M had memory power issues that did not allow it to clock very high... the highest clock speed I remember users getting was what... 2200 average memory core? If it can't at least go to 2500 memory, then a +500 mem OC on the 870M (which should be possible as the 780M can do it) would outstrip anything memory-wise that a 680M could do. The core count is the same too, so the 870M should perform (and OC) as well or better than the 680M could. If this is the case, then the 870M should be a clear winner. For the 680M to win, it'd need to hit a stable 2500 mem clock (assuming that a 3000 mem clock is the highest stable clock the 870M can go to) AND be able to overclock its core to match any light OC the 870M could do. Otherwise, the 870M is just the better card, mainly due to the increase in power being applied to the memory (if I remember right, this was the problem the 680M had when people tried to OC its memory).

If this isn't even the case though, and the OC'd 680M can beat the OC'd 870M in memory while attaining the same core speed and being stable, only a few games would benefit from the (likely slight) memory bandwidth increase. For comparison, the 660Ti was a very powerful card, and kept up in so many games with the 670 that quite a few people simply got a 660Ti for cheap power and then got a second one when they felt an upgrade was timely. The 670 was ~$100 extra, and OC'd better at the time than the 680 which was ~$200 more than the 660Ti... so two 660Tis for ~$50-100 more than a single 680 would give people far more power than a single 670 or 680 could ever provide. So yeah. The 870M is pretty well done, really.

Now if the 680M could both OC better in core AND mem bandwidth than the 870M could, while remaining stable, not overheating AND without severely reducing card longevity with heavy overvolts etc... then 680M's your champion. I'm a bit skeptical though, and I doubt it could do that.

 

iirc the 870m only has 24 ROPs vs the 32 in the 680m. So there's more to it than just memory and core clocks.

Also, getting the 680m to 2200mhz (400mhz OC) on memory would give pretty much the same increase in bandwidth as increasing the memory in the 870m by 500mhz.

 

It's a bit less, actually. ~140GB/s versus 144GB/s. Not gonna make a huge diff, but it should work.

As for the ROPs... their core count is the same. I don't know if the number of ROPs would make that much of a difference if they have the same number of total cores, but if it does, I'd like to find out in what way. It'll be interesting information to me.

Either way, however, I do not know the maximum OC with the 870M on the memory/core, which means it could possibly easily surpass a 500MHz memory OC. The 780M handles +500MHz core on a 256-bit mem bus easily, I'm sure the 870M could at least go a bit higher. I still think that unless the 870M's stable OC range is below the stable range of the 680M, the 870M is the better buy. Unless, as you mentioned R3d, the ROPs make that big of a difference even though the shader count is the same.

 

Actually I just checked it. The ROPs is probably referring to the memory. 256 (bit mem bus) divided by 32 ROPs = 8, and 192 (bit mem bus) divided by 24 ROPs = 8. So it matches there. I still don't know what it means performance-wise, but after I typed out all the above the correlation clicked in my head so I just ran it through the calculator on a hunch.

 

But which one is a bit cooler at stock or are they the same?

 

GTX 680M will be cooler.
The GPU clock have increased from 720MHz to 940MHz+.
The GDDR5 is high voltage VRAM and it runs at 1250MHz while 680M have low voltage VRAM and runs at 900MHz

 

The ram did not like over voting that much either , got to about 1350mhz max.

I got it to around 1180-1200/1375 for benchmarking IIRC.

 

I think it depends a bit on what memory brand you get.
HaloGod got his 860M to 1600MHz+ but HTWingNut had problems even at around 1350MHz like you do.
Strange that the OEMs don`t just stick with the best VRAM instead of making it more difficult to keep up for us customers. I can`t imagine there is so much money to be saved on using the cheaper brand.

 

My previous 680m OC'd pretty decently.. It ALMOST performed identically to my 780m (when 780m was stock) with a slight OC.. About +200mhz core and +500 on memory if I remember correctly. It was within 10% with a very cold and safe OC. The 870m is still a good GPU stock and OC'd.

 

bettwen both gtx680M and gtx870m from me for GTX680M big point, or another scenario you have still GTX780M - it's better than new GTX880M

 

To OP: I've been gaming with an 870m for the past week and i'm very impressed with its performance. It has ran all the games I have installed so far in full settings @1080p without any issues (CSGO, GW2, Injustice).


Offtopic: How is the 780M better than the 880M? Looking at the spec sheet for both of them suggests the 880M is slightly better performance wise (around 10%). Unless you are talking about an overclocked 780M vs an overclocked 880M

Cheers

 

The 780M's unlocked vBIOS makes it better. The 880M (as far as I know, at this writing) has not had an unlocked vBIOS release yet, and the 8GB of vRAM makes it use slightly more power/run slightly hotter if I remember right. Essentially, they are the same card with different stock clocks excepting the memory size.

 

The 870M/880M modified vBIOS have been release by svl7 at this point and they are just as unlocked now, if not more.

http://forum.techinferno.com/genera...modified-clocks-voltage-tweaks.html#post23432