About Bottlenecks..

[jellars]

Hey, First time poster, long time reader.

I've seen the word bottleneck used alot when people have a old CPU like Athlon XP 2000+ and are thinking about upgrading to a current-gen like a 7900GT. So heres my noob question.. How exactly do you know when your processor is bottlenecking your video card or any other peice of hardware for that matter..

 

[jamesgoddard]

A PC will only run an app as fast as the slowest componant.... That about sums it up.

 

[prozac26]

In gaming, the video card most of the work, something like XP 2000+, will hold back some framerates.

Make sure the parts are same time-period, or generation, and you'll be fine.

 

[cleeve]

Depends on the game.

Some games are heavily CPU bound - like flight simulators. Others, graphically bound.

Alot of new titles are both CPU and GPU bound. But in most cases, if you upgrade, it's going to have a positive effect on your framerates regardless.

But you don't want to tie something old and high end together. Doesn't make sense. For your XP 2000+, an X800 XL/X850 PRO or 6800 GT would be a good match. You can get em on ebay for pretty cheap, and they are still powerful cards.

 

[Talon]

I think bottlenecks are a waste of space personally. I mean WHY can't they just fill the bottle up to the cap with beer? WHY???


Sorry, I see the question has already been well answered and I couldn't resist. Only other way I can think of is to run your own benchmarks and see when you hit a cpu wall with your own system etc.

 

[jellars]

Well I dont actually have a Athlon 2000 was just using it as an example. But I'm asking the question based on buying a new PC. I was thinking of buying a Dual Core and a ATI R600 when the time comes and maybe there after only upgrading the Video card, so I was wondering like how long till a dual core processor would eventually be a bottleneck.

 

[Guest]

You basically have to read reviews.

How do you know a game is bottleneck by the CPU?
Ex.: it does 60 Frame Per Second at 800X600 and does 59FPS at 1600X1200

How do you know it's bottlenecked by the GPU?
it does 200FPS at 800X600 and 15 at 1600X1200.

(extreme but you get the point).

A balanced computer is always better. Usually for games a decent CPU and a GOOD GPU, is better then a better CPU with a lesser GPU.

The CPU is less important but does play an important role, especially in AI/Physic intensive game.

 

[godman]

a few of years, until 2009 or so when intel releases their nahlem quad? core uarch then maybe we will see a big leap in performance, though its only speculation

the other posters are right, get a system with all components from the same timeframe.... and as labbby said a balanced system is better than an unballanced one

 

[piratepast40]

I'm also wondering about "bottlenecks" and what constitutes a "balanced" system and don't quite understand the answers given thus far. Specifically, what do I look for to say I have a "balanced" system?

My system is an Asus A8V Deluxe (AGP), AMD3400+ (s939 - 2200 mhz), 1 gig (2 x 512) of Kingston HyperX PC3200, and an nVidia 5200 video card. Obviously the video card is a little weak. If I upgrade the video card to a 7800GS, will the CPU be able to utilize the power of the card and what numbers should I be looking for in the card and CPU specs?

I know I could use another gig of ram and intend to do that with 2x1gig sticks and perhaps put my existing 2 x 512 sticks in slots 2 and 4 for a total of 3G but a slowdown to 333mhz.

Sorry if this seems like a dumb question and thanks in advance.

 

[smitbret]

The CPU will probably be just good enough in most cases. That GPU is awful. The 5xxx series from nVidia was generally just a bad family of GPUs. I would think that a 7600GT would be a decent fit for this system. You could always get a better one and then upgrade the CPU later rather than invest in a new GPU twice.
-Brett

 

[pauldh]

In gaming, the video card most of the work, something like XP 2000+, will hold back some framerates.

What you have to watch is having enough minimal CPU power for the particular game that you are not purely cpu bound. For example, the past 3 Need for Speed titles would not run max details with a XP2000+. Once you are above about a XP2500+ it's basically a few more fps as you said until the particular GPU becomes a bottleneck. But if the cpu scaling gets too low for the game you can reach below playable settings no matter what resolution/GPU. Only option then is to reduce detail levels or OC the dickins out of the CPU.

 

[pauldh]

I wouldn't worry too much about bottlenecking an AGP card with any A64. A few fps here and there, sure, but nothing significant. I'd even pop a top of the line X1950 pro AGP in with an A64 3400+. This changes in PCI-e and moreso higher end SLI/crossfire. I would not put a 8800GTX or even SLI 7900GTX's in with an A64 3400+. But again, a single X1950 pro PCi-e, sure why not.

I should add, my own thinking is, when you go below a 2.2GHz AXP(3200+ or OC'ed barton) or P4 2.8C, then you may want to stay down in 7600GT or even lower... X850 pro range. But If you have either of those or better, then Stick any AGP in there you can afford as you can take advantage of extra power with higher resolution/eye candy. Also, When you are talking P4B 2.4GHz, XP2400+ or lower then definatelty don't spend too much on an AGP. Maybe X800GT tops. or better yet sub $100 6600GT / sub $75 9800 pro range.

 

[piratepast40]

Thanks for your input Bret.

I think the 7600GTs in AGP are scarce as hens teeth. But what makes a certain card "match" a CPU?

I'm really stuck in the "should I or shouldn't I" dilema. The 939 chips aren't in production anymore and who knows what prices are going to do in the future. If I stick with my current mobo, It'll cost me about $800 to upgrade to what I want (roughly $230 each for ram, video card, and X2 4600 cpu, plus another $80 or so for a bump up to a decent 550w power supply). If I want to upgrade to PCIe with my existing 939 socket, the price jumps about abother $100. If I go with an AM2/PCIe board and chip with 2G Ram and a decent video card, I have the same amount invested but with current generation components. Actually, this is the first time I've actually done the math on the upgrade and the picture gets pretty darned clear! :idea:

 

[flasher702]

You basically have to read reviews.

How do you know a game is bottleneck by the CPU?
Ex.: it does 60 Frame Per Second at 800X600 and does 59FPS at 1600X1200

How do you know it's bottlenecked by the GPU?
it does 200FPS at 800X600 and 15 at 1600X1200.

Exactly. You have to do a bunch of tests on bunch of different systems. In practical terms that means comparing lots of reviews. Toms has some decent ones (although they don't go back very far for older hardware) where they benchmark a bunch of CPUs using the same high-end GFX card and then benchmark a bunch of GPUs using the same high-end CPU. It varys from one application to the next.

So, if your CPU or RAM were a "bottleneck" in an application and you upgraded your GFX card you would see little to zero improvement.

 

[flasher702]

I think the 7600GTs in AGP are scarce as hens teeth. But what makes a certain card "match" a CPU?

It depends entirely on what you're doing. To "match up" a CPU and a GPU it's the mostly just the *software* that is being bottlenecked, not the hardware (slow RAM, frequency divisors and bus speed mismatches could bottleneck both of them at the hardware level, but that's another discussion). If you're encoding video you don't need a GFX card at all but will need all the CPU power you can get. Conversely some games will run just fine on an AM2 Sempron but need all the GFX power you can give them.

Oh, and if you're looking at AM2 you should seriously consider a C2D system instead, for the same amount of money you should be able to get more performance.

 

[piratepast40]

Thanks to everyone for input on this - I now realize it's more complicted than just comparing CPU and GPU numbers. Oh - thanks to Jellers for starting this thread!

I just realized I can get one heck of a lot more mileage out of my board with an upgrade to a 4000+ CPU for only $119 at newegg. That should significantly improve system performance and I'll be able to wait a little on a video card to see if the prices on top notch AGP cards come down. Should be able to do my upgrade for about 1/2 the price I had originally looked at.

 

[pauldh]

I just realized I can get one heck of a lot more mileage out of my board with an upgrade to a 4000+ CPU for only $119 at newegg. That should significantly improve system performance and I'll be able to wait a little on a video card to see if the prices on top notch AGP cards come down. Should be able to do my upgrade for about 1/2 the price I had originally looked at.

Let me get this straight. You are planning to go from an A64 3400+ to an A64 4000+ but stay with the FX5200? No offense, but if you do any gaming at all, that's a downright aweful plan IMO. The A64 3400+ is not that bad, but the FX5200 is completely lame. I'd stay with the 3400+ and put money into a video card. $140 X850 pro for starters. Or a $250 X1950 pro in a couple weeks, or if you must buy now, want SM3.0 and a decent card... a BFG 7800GS for $199 AR on Newegg. Anyway, there isn't a game out there that won't play well on an A64 3400+ with 1GB mem, but most to all games won't play well on an FX5200. That's the place to start upgrading as it's all you really need. And if you are doing CPU, memory, and a new video card, by all means switch to PCI-e.

 

[piratepast40]

Let me get this straight. You are planning to go from an A64 3400+ to an A64 4000+ but stay with the FX5200?

Oh - I agree with you - Will definately be replacing the video card but wanted to grab the 4000+ SanDiego while the price is low and before it's impossible to find them. The only "game" I use is MS Flight Sim 9 and it's extremely CPU intensive. FSX is even more so. From what I understand, the SanDiego 4000+ is a large boost over the 3400. If I'm wrong on that - don't hesitate to say so.

Besides that, trying to get dual use out of the 4000+ by putting it my laptop after the warranty is up (currently has a 3200+). That way, at least one upgrade part I'm buying will have life after I replace my desktop system - probably next fall after things shake out with Vista and DX10.