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Learning about Bottlenecking

Last response: in Graphics & Displays
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May 21, 2009 6:20:27 PM

Hi guys, I'm new to Tom's Hardware... this place looks like a GREAT community.

I was wondering if you could help me. I have a pretty limited knowledge about hardware (i.e. I'm not a complete noob, but enough to clasify as one), but don't know much how to distinguish which components can cause a bottleneck in performance. I was wondering if you guys can provide with a little tutorial or so to understand this.

I ask because I'm looking to upgrade my graphics card to either a GTX 260 Core 216 or make the jump to the GTX 275. Obviously, if all the other components are bottlenecking, then it's not worth the jump.

C2D E660 @ 2.4GHz (1066 FSB)
4GB DDR2 @ 667
1KW PSU
(still running on XP, if that matters)

I'd provide the manufacturers, but I'm not sure since they're all Dell provided. :??: 
(was going to build my own rig, but I've had issues in the past)

Thanks for the help!

More about : learning bottlenecking

May 21, 2009 6:32:20 PM

Ha! Almost simultaneous post about exactly the same thing! Great minds think alike or is it idiots seldom differ....I'm not sure ;) 

AC
a b U Graphics card
May 21, 2009 6:33:28 PM

Every computer has a bottleneck in it. As far as physics goes the term bottleneck simply means an aspect of a system (complex or not) that limits the overall output to a stronger degree than the sum of the other parts(linearly or not). Often times in the hardware world we use the term to point out which component is slowing the system down the most, obviously it is far more complicated than that. Computers are also not linear, unlike a valve on bottle :) 

Ina simple system we could have two parts, A and B, A gets data, gives it to B, who then saves it. The total speed at which data could be stored would be equal to the slowest member of the simple system. a computer has hundreds of parts, and they are not in a fire line like that... A talks to C who talks to F who talks to A who talks to Z who feedbacks to J.. and so on.. Thus upgrading a part of a computer with almost always increase performance, it will asymptotically approach no gains though..

Your CPU will hold back a 275 a bit, it wont hold it back enough to make the upgrade pointless though. You will see improvements over what you have now, even over a 260. Obviously if you improve the CPU the gains wuodl be grater, and the scaling (diffrence between a 260 and 275) would also be greater.

Generally, if you here the word "bottleneck" aroudn here people are talkign about a level of bottle neck that makes an upgrade not worth it (Like if you wanted to go SLI 285's on that CPU).

I really could go on about system design (hardware or in general processes like fusion in a star).. But they have degrees in these things for a reason.. a forum post cant do it justice.
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a c 201 U Graphics card
May 21, 2009 6:34:17 PM

Whats your current graphics card and whats your current resolution? There isnt much point in upgrading if your current one can handle your monitor just fine.
a b U Graphics card
May 21, 2009 6:40:06 PM

hunter315 said:
Whats your current graphics card and whats your current resolution? There isnt much point in upgrading if your current one can handle your monitor just fine.


Also correct.. an often overlooked bottleneck is what you are asking your computer to do.. If you want it to produce an 800*600 resolution even a low end card wont ahve to work up a sweat. A discrepancy in resolution will hurt your scaling much more than a slow CPU.
May 21, 2009 6:40:32 PM

ac3144 said:
Ha! Almost simultaneous post about exactly the same thing! Great minds think alike or is it idiots seldom differ....I'm not sure ;) 

AC


In this case, I'd say it's the latter. :kaola: 

daedalus685 said:

...
Generally, if you here the word "bottleneck" aroudn here people are talkign about a level of bottle neck that makes an upgrade not worth it (Like if you wanted to go SLI 285's on that CPU).
...


Thanks! I know obviously I can't learn everything about graphics processing through a forum thread, but I do have "enough" knowledge about the whole process to follow along the basic points (if not, I'm never afraid/lazy to do my hw).

I know the answer is far from simple, but what numbers/specs can we look for and interpret to understand how a specific component is causing the bottleneck?
May 21, 2009 6:41:53 PM

So Daedalus, in general, the CPU, GPU and MOBO are the most important and looked at as a whole rather than value x is less than value y therefore value x will BN value y. Is that more or less correct?

Also, you are saying that BN'ing is a relative term and I'm guessing that only if there was a serious mismatch in the above components would you notice a difference?

Thanks, AC
May 21, 2009 6:43:20 PM

Psylentstorm..you and I need to stay in at luchtime and do extra homework...;)
a c 201 U Graphics card
May 21, 2009 6:45:38 PM

Where the CPU bottlenecks the GPU depends heavily on the game, some are more graphics intensive and even a midrange CPU wont bottle neck it; however those that are CPU intensive, if you look at some of the card reviews you see that all of the frame rates at no matter what the graphics setting are about equal. The point at which the CPU bottlenecks the GPU is best determined experimentally and on a per game basis. If you like to play with AA and AF on then your CPU is less likely to be your bottle neck as those fall onto the GPU.
May 21, 2009 6:48:11 PM

hunter315 said:
Whats your current graphics card and whats your current resolution? There isnt much point in upgrading if your current one can handle your monitor just fine.


Right now I've got the 8800 GT, but my sister's card just shut down, so I'm going to pass this on to her and upgrade mine. So it's more of a replacement than it is an upgrade, I guess.

Off the top of my head, my native resolution is 1680x1050, mostly used for FPS's and the rare RTS if I ever find one I like.

a b U Graphics card
May 21, 2009 6:48:52 PM

Yes, AC.. Bottlenecking is very much a relative term. A missmatch will always exist in every system. My CPU holds back my graphics cards a bit, some people it is the other way around. But it doesnt make much of a difference.

Only with a large missmatch woudl you hit enough diminishing returns to make an upgrade a silly investment. (For example.. people have come here with SLI 285's, ona CPU similar to yours running at 15" CRT resolutions... )

When we look at a computer system usually we consider it a simple system, The CPU, the memory, the GPU and the task you want it to do (usualyl resolution and game settings). Any one of those can bottle neck the others, but it is not as simple as A is twice as fast as B therefor the system only goes as fast as B. Upgrading A to be three times as fast as B still improves performance, but the larger the gap the less and less you will notice an equally stepped upgrade.
a b U Graphics card
May 21, 2009 6:50:23 PM

You will certainly notice a difference form teh 8800 psy, though at that resolution a 260 is probably plenty.
May 22, 2009 6:02:05 AM

Daedalus,

You mentioned my e6600 may hold back the new gpu a bit. Just wondering if you had any recommendations for a cpu upgrade.

Seriously, you've all been great help, and I'm definitely interested in learning more.
!