8970m overclockable?

I've read the 8970m is basically a 7970m but overclocked, is this true? If so then it means the 8970 has very little room to be OC because it already has!?
Can anyone confirm this to me.
Thx.

 

Possibly but possibly not. Let me explain.

The 8970M is exactly the same as the 7970M, except with 50MHz higher default core clock. The only difference is the 8970M, being the more recent batch on the chip production line have higher average ASIC quality; simply meaning better average overclocking capability. This is why the default clocks have been increased. However, that 50MHz is not a huge increase. I'd wager that the improvements in ASIC quality negate the 50MHz default clock increase; thus meaning that both 7970M and 8970M have very similar overclocking capabilities over their stock clocks (unlike the upcoming 880M which has +143MHz advantage on the stock 780M, which is quite a lot more than a +50MHz increase the 8970M has, and so early reviews of 880M have shown less overclocking headroom than the average 780M).

This is not science. This is only my personal guesstimations. Someone else will hopefully be able to help you more.

 

When OEMs design chips, they target a frequency that is higher than what customers are expecting. The desktop 7870 and the 7970m are the exact same chip. If the 7870 can clock at 1GHz so can some 7970ms (and by extension, 8970ms). I say some because chips made from the surface of the wafer generally have more defects than chips made from the inner layers. The ones from the center of the wafer can generally clock faster and AMD sells those as the Desktop 7870. It sells the ones that don't meet timing at 1GHz as the 7970m. That is why there's some people that have been able to overclock their 7970m to 1050. Those are the lucky ones. So if this same 7970m was branded as a 8970m, you'd have ~150MHz of overclocking headroom. Being a more recent batch usually does not improve quality unless the fabrication process is very immature. However, TSMC usually test their processes far in advance so processes are mature by the time companies like AMD license them.

Now to get to your question. 20% overclock is usually quite a lot. So if you are able to get to 1050MHz on that, I'd say you are lucky. Aim for that. If your laptop craps out on a game at lower frequencies, well, then that is what you can do at max. Also, some are able to go higher than 1050 but not on the same voltage. That's when overvolting comes into play.

 

how to explain the ram then? some can oc higher some lower.

 

Same story. RAM chips are also made from polySi.

 

that means better quality ram goes to desktop card and poorer quality goes to mobile card? but the 7870 desktop card's ram is same as 7970m ram 1200.

 

i can go up to 1055 with stock voltage and max 1115 at 1.1v on my 7970m

 

The RAM quality is not better of worse. Just because it was fabbed from inner Si layers doesn't mean its quality is worse. Just that it is less tolerant to being overclocked.

Yeah. So?

 

so the manufacturers dont need to pick inner or outter layers for mobile or desktop cards, right?

 

Mobile parts usually have better electrical characteristics because of TDP restrictions. This would describe things like leakage, voltage needed to hit a clock target etc. ULV parts would be the pick of the bunch.

"Defects" would describe something that doesn't function properly or at all, which is why they fuse off shaders, cores or cache.

It's safe to say the average 8970M would have better electrical characteristics than the 7970M, if for no other reason than time. 7970Ms were being fabbed when the 28nm process was only a few months into full scale production. It like any other process has matured.