GTX 690 being bottlenecked by an 2500k

[LaMonster32]

This is my first time on the forum and this is my first thread so I hope
you will be polite and help me.

So my question/problem;

How far do I need to overclock an 2500k to be able
for a GTX 690 to use all of his potentials ?

My question differently described;

At which point (Ghz) an 2500k doesnt bottleneck a GTX 690 anymore ?


I've done some research but couldt find a clear answer, I've seen
some videos on youtube where people use an 2500k at 4,6/4,8 with a 690
but I still dont know if the 2500k is bottlenecking the 690 at that point and also I could't find any clear graphs.

I hope you people can help me answering this question.

 

[SeekaX]

it really doesn't work like that.
also welcome to the forums.
a bottleneck is always related to the application. so there are games where a 2500k won't bottleneck a 690 because they are GPU intensive and not really cpu demanding, in others the 2500k will bottleneck like crazy because it's cpu intensive.
but really, a 2500k should do good enough in general with a 690, you don't seem to be much of an experienced overclocker so your goal should definitely not be 4.8GHz. be modest, start with something small like 4.2GHz. it's better to take small steps than to ruin your cpu because of being impatient.

 

[s3ns3]

~ 4 - 4.2Ghz

 

[LaMonster32]

Thank you for you answer SeekaX,
also thank you for the advice.

I´m not planning to do it but I´m just curious,
let´s imagine an (unrealistic) scenario;

A very GPU intensive game/benchmark tool which could take a GTX 690
to a 100% GPU load, under which point (GHz) would be
an 2500k the cause of the bottleneck instead of the GTX 690 with a 100% GPU load ?

 

[nepas]

depending on what you were running,I would look at the HDD slowing things down before the CPU/RAM

 

[SeekaX]

Thank you for you answer SeekaX,
also thank you for the advice.

I´m not planning to do it but I´m just curious,
let´s imagine an (unrealistic) scenario;

A very GPU intensive game/benchmark tool which could take a GTX 690
to a 100% GPU load, under which point (GHz) would be
an 2500k the cause of the bottleneck instead of the GTX 690 with a 100% GPU load ?

as i said before, it's all application related. every application behaves differently, in a benchmark made specifically for GPUs the CPU should barely ever be the source of a bottleneck. not even with a dual core probably.
and then there is that thing called silicon lottery, which means that every chip behaves differently again. so you can't say at which exact frequency the CPU won't be bottlenecking the GPU anymore.

 

[LaMonster32]

as i said before, it's all application related. every application behaves differently, in a benchmark made specifically for GPUs the CPU should barely ever be the source of a bottleneck. not even with a dual core probably.
and then there is that thing called silicon lottery, which means that every chip behaves differently again. so you can't say at which exact frequency the CPU won't be bottlenecking the GPU anymore.

Again thank you for the help,
I understand it´s difficult to answer.

I´m also aware of the "silicon lottery", I have done a few OC´s on SB/IB
and older architectures, only I didnt have to time to play with mine.

I hope I can squeze atleast 4,6/4,7 out of mine 2500k, I've no
idea what the tempertures are going to be but do you people
think a H80 will be enough ?

It´s not about the money but anything bigger just wouldnt fit.

 

[nepas]

a 2500k@ 4.6 should be easy(mine was 4.8 24/7)chips clock for fun these days.


The old rule of thumb was if a quad is over 3Ghz it won't bottleneck(the effect on Q6600's springs to mind).(this is IMO) from what I have done with my old 25k,there was NO bloody difference once the chip went past 4.5,until that point you could see and measure a difference in fps with every 100mhz you tried,after that,it was down to 1-2 fps(which is slap bang in the middle of the avg fps rule).

Another thing to bear in mind is if the PCIE slot is pushed to its max(and before anyone starts,the answer is NO on a 2.0x16)

 

[alienware]

Thank you for you answer SeekaX,
also thank you for the advice.

I´m not planning to do it but I´m just curious,
let´s imagine an (unrealistic) scenario;

A very GPU intensive game/benchmark tool which could take a GTX 690
to a 100% GPU load, under which point (GHz) would be
an 2500k the cause of the bottleneck instead of the GTX 690 with a 100% GPU load ?

I'll do my best to explain this. A CPU is only a bottleneck when the app or game you run depends on CPU speed. I have a CPU that's locked to 3.3ghz in Turbo (or 3.4 on one core) and in games with 670s in SLI (very similar to a 690) I constantly see them at around 95-100% use.

Now in a benchmark that also tests your CPU my scores are heavily reduced due to the CPU.

However in games I rarely see low FPS. This is mostly because a bottleneck causes problems at the top end, and as long as the CPU is fast enough to cope with what you are doing you will only see a drop in the max FPS.

What I'm basically saying is by the time you will see a bottleneck on a 2500k at say 4.4ghz it won't really matter unless you are chasing benchmark scores.

In 3dmark 11 and 3dmark Firestrike I score right about what I should on my GPU score. Thus I haven't bothered buying a K chip as it would only be for that and to improve my Physics scores and overall end results.

Obviously what matters is real world stuff like gaming where my CPU is more than adequate to take care of what it needs to

 

[LaMonster32]

Thank you AlienALX and nepas,
that were the kind of answers I was looking for.

I was aiming at a overclock at 4,5-4,8 on my 2500k,
will a H80/H90 be enough to keep the tempertures under 75 C ?
(I'm aware of the "silicon lottery" but I have to ask)

If not I wil try to keep him in a range of <4,5 because my case
wont take anything better/bigger.

 

[alienware]

Most 2500ks Ive seen will do 4.5ghz. Anything higher seems to be down to luck really.

4.2 or so (as mentioned earlier) will be fine tbh.

 

[SeekaX]

also performance in games doesn't vary a whole lot above 4.2 GHz. but you should be able to push beyond 4.5GHz without any problems with an h80i.

 

[LaMonster32]

Thanks for the help,

I will order a H80i, at first instance I wanted to use a H90
but I just checked my system and there is no way I could
squeze a H90 in it.