FSB limits performance on Intel?

[kassler]

Check this

http://forums.guru3d.com/showthread.php?p=2740928

I think I have found the culprit: It's the FSB!

I did the following:
- changed my CPU clock from 2400 (9*266) to 1600 (6*266) - no change, 27 FPS
- changed my memory clock from 400 to 266 - no change, 27 FPS
- changed my FSB from 266 to 333 - success, 34 FPS

The FPS actually changed exactly according to my FSB change - a 25% increase in both cases.
It might still be memory bandwidth though, since with Intel CPUs the FSB is the limiting factor.
I have never actually seen any game that is limited by FSB or memory bandwidth nor any mention of such behaviour. I think we have found a new type of bottleneck here.

EDIT: I just ran another test: I decreased the memory clock to 266 while keeping the FSB at 333: Still 34 FPS. So it actually is the FSB.
Time for Nehalem, I'd say.

 

[1haplo]

Intel is still faster then AMD

 

[NMDante]

I can play your silly game too:

Hi

I recently got an AMD Phenom a decision that I am regretting now.

I've got a
* ASUS m2n-sli
* AMD Phenom 9500
*Thermaltake Soprano with a 430W (XP5500NP)
* 4Gb = (2 Kits of (2*1 GB Ram A Data)) 800
* Geforce 7900GS
*19 Screen (1280x1024)

I currently have another computer that's a p5n-e sli Core 2 Duo E6600 4 GB of ram and a 8800gts(320mb), same case but with a 22" monitor. This computer literally smashes the performance of the AMD.

I even tried putting the 8800gts into the Phenom and it only improved graphic performance mildly. The Core 2 Duo beats the Phenom even running at 1680x1024 vs 1280*1024.

The games I have tested it with are TF2 and Supreme commander.

Supreme commander is interesting as after 1 minute the processor performce deteriorates even just playing a 1 on 1 AI. This thing runs it worse than my old Athlon 3500 single core, even a 3800+ X2 I borrowed of a friend works better.

Have I configured something funny in my system or is it something else?

I know the Phenom have a bug that a Bios updates has to fix
The board I'm using is a AM2 (not AM2+) which has phenom compatibility
I heard AMD sent benchmarkers a core which didn't have these faults and higher clock speeds just to win. Is the phenom just a huge lemon?

Should I ?

http://forums.whirlpool.net.au/forum-replies-archive.cfm/944295.html

 

[NMDante]

Since forum posts now equal reliable sources to you - here is another, running the same game, and much more recent:

i have a phenom 9500 2.2ghz quad core, 3gb ram, 8600gts. In any town i barely get 30 fps. out of town i get a wonderful 50 fps. Now what i dont understand is how i only get 30 in town. So what i did is went to a place where i only got 27 fps and i saved it and turned the res down to 800x600 and i got the same 27 fps. what is wrong with my setup

http://answers.yahoo.com/question/index?qid=20080708190039AAuguOO

So, go wander through more forums looking for the magical saturated FSB.

 

[jimmysmitty]

The TF2 is a great FPS to use for true CPU performance since Source is very CPU limited.

Of course I almost feel like this was made up. But I can't go to the sit ehe linked so meh.

Also I like that the guy never posted his multiplier for the 333FSB.

 

[kassler]

So, go wander through more forums looking for the magical saturated FSB.

Read the text! He did some informative OC to check where he was getting more performance and found out that for that game it was the FSB that was the bottleneck. This could be the case why Intel users notice a performance gain when the OC.

 

[NMDante]

Read the text - Phenom having same issues. Guess it's the Phenom's FSB too?

 

[jimmysmitty]

Read the text - Phenom having same issues. Guess it's the Phenom's FSB too?

LMAO

+1

Its more to do with the game itself than anything. Its poorly optimized. And at the res he was playing a poorly optimized game engine will kill your FPS no matter what hardware you have.

 

[kassler]

Read the text - Phenom having same issues. Guess it's the Phenom's FSB too?

Phenom doesn’t have a FSB. Read about the hypertransport here: http://en.wikipedia.org/wiki/HyperTransport

fsb: http://en.wikipedia.org/wiki/Front_side_bus

Nehalem have removed the FSB

 

[jimmysmitty]

Phenom doesn’t have a FSB. Read about the hypertransport here: http://en.wikipedia.org/wiki/HyperTransport

fsb: http://en.wikipedia.org/wiki/Front_side_bus

Nehalem have removed the FSB

You do understand it was a joke right? I mean.... come on. Hes not an idiot.

Man you must not have comedy in your area.

 

[kassler]

You do understand it was a joke right? I mean.... come on. Hes not an idiot.
Man you must not have comedy in your area.

Aha, I do comedy in my own language

 

[epsilon84]

Aha, I do comedy in my own language

Yeah, and the same FSB joke is getting kinda old...

 

[jimmysmitty]

I just realized something..... Your own post here is in a way proving you wrong. You talk about how the FSB limits performance since it cannot access memory faster. Well if this was true then when the guy lowered his memory clock speed he also lowered his memory bandwidth.

But still its more of the games fault than the CPU here.

 

[NMDante]

Phenom doesn’t have a FSB. Read about the hypertransport here: http://en.wikipedia.org/wiki/HyperTransport

fsb: http://en.wikipedia.org/wiki/Front_side_bus

Nehalem have removed the FSB

No way. Really?

So, explain why the Phenom system has almost the exact same FPS as the Intel "FSB problem" system.
Both are claiming to have low FPS, no matter what the resolution is set at. We are waiting for your explanation, since it can't possibly be a GPU or game coding issue. It must be an interconnect problem, right?

I'll be waiting for your technical explanation.

 

[the last resort]

but a rockin AMD = Intel with FSB problem
hmmm
o.0?

 

[Ancient_1]

I am not familiar with the Rampage Formula but on any of the later Intel chipset boards I have seen (p35and later) it doesn't allow setting the mem speed lower than 1:1 and don't see how he ran at 333 fsb with a 266 mem speed. I wonder if he just changed the strap rather than slowing the memory down to 266. If so how credible is anything else he said?

Also just look at the article that Toms just did on the p45 and see how much gain was shown going from 1333 to 1600 on the fsb (should be quite noticeable if the fsb is a bottleneck).

http://www.tomshardware.com/reviews/intel-p45-chipset,1961-15.html

From that article you can show that 1333 is faster than 1600 or that 1600 is faster than 1333 depending on the test result you pick.

We ran all benchmarks at least three times, and used the average result of all benchmark runs. As you will see, there is no clear performance winner, as the differences are too small. This includes the enthusiast X38 and X48 chipsets, as well as the mainstream P35 and P45 chipsets, and 1333 MHz versus 1600 MHz—the effective difference is close to zero.

 

[MU_Engineer]

Check this

http://forums.guru3d.com/showthread.php?p=2740928

I think I have found the culprit: It's the FSB!

I did the following:
- changed my CPU clock from 2400 (9*266) to 1600 (6*266) - no change, 27 FPS
- changed my memory clock from 400 to 266 - no change, 27 FPS
- changed my FSB from 266 to 333 - success, 34 FPS

The FPS actually changed exactly according to my FSB change - a 25% increase in both cases.
It might still be memory bandwidth though, since with Intel CPUs the FSB is the limiting factor.
I have never actually seen any game that is limited by FSB or memory bandwidth nor any mention of such behaviour. I think we have found a new type of bottleneck here.

EDIT: I just ran another test: I decreased the memory clock to 266 while keeping the FSB at 333: Still 34 FPS. So it actually is the FSB.
Time for Nehalem, I'd say.

I can think of three reasons that he may have had better performance <i>initially</i>:

1. Northbridge I/O bottlenecking being relieved by higher northbridge clock speed. Northbridge clock speed is the same as the FSB clock speed, so if there was an internal northbridge I/O bottleneck this would most certainly help. He has two GTX280s in SLi and the PCIe x16 slots come from the northbridge, not the southbridge, so it is certainly a possible culprit and this is the kind of result you would see if you were GPU-limited and your GPUs were I/O-starved.

2. His memory straps aren't what he thinks they are and the strap stayed the same when he bumped the FSB clock from 266 to 333, overclocking his memory. That can give you better performance in a memory-intensive application.

3. The FSB actually was the bottleneck.

After reading his edit, I am almost certain it is #1 if he is accurate with his "I set my memory to 266 MHz when the FSB was at 333 MHz" bit. It makes #2 incorrect and #3 unlikely. An FSB clocked at 333 MHz carries up to 12.7 GB/sec while dual-channel DDR2 at 266 MHz (DDR2-533) only outputs 8.5 GB/sec. The FSB in a Core 2 Quad *does* carry information both between dies as well as to and from the northbridge, but inter-die FSB congestion is unlikely. Why do I say that? He was playing Oblivion and that is not very multithreaded: http://www.tomshardware.com/forum/240359-28-core-quad-performance-oblivion That means that there isn't going to be a whole lot of cache coherency traffic between the two dies and thus the FSB is basically going to be used for CPU <--> RAM data transfer. We'd need to get a hold of his system and try a few things such as a single-die C2D and play more with FSB, northbridge, and RAM speeds as well as using a single GPU to accurately tell what's going on, but I *highly* suspect it has to do with the northbridge being swamped with PCIe traffic from the two GPUs.

 

[Ancient_1]

It is an Intel chipset which means no sli so its a single card. It wasn't the original poster that is quoted in the post here it was Reaping_Ant on post #6.

 

[jimmysmitty]

I have a P35 mobo and it doesn't have a ratio setting but lets you select the memory frequency. I haven't had to mess with it since I got it to a stable 3GHz and the memory to a 1:1 @ 1333MHz so I can't remember if you can go lower than 1:1.

MU I will only disagree with you that its not only Intel rigs that have problems with this game, it is also AMD rigs. This game has a pretty badly optimized engine and I need to try it on my new system but on my old one I had to cut AA and AF @ 1024x768 and move up to 1280x1024 (to try to get the same AA/AF effect). And I had a pretty dam kick ass system for the time, Pentium 4 EE 3.4GHz, X850XT and 2GB DDR800. It ran pretty smooth then but I had to have HDR off or it would kill my system.

 

[JDocs]

First he states that "changed my CPU clock from 2400 (9*266) to 1600 (6*266) - no change, 27 FPS"... Erm that means that the CPU is 30% slower at the same FSB, 30% less data transfer but still the "FSB is saturated"... Not likely...

Second item "changed my FSB from 266 to 333 - success, 34 FPS", he doesn't mention if he lowered the multiplier to compenstate. If he didn't well then it does prove that he is an idiot because then his clock speed and FSB both went up by 25% and performance increased by 25% but lower the clock speed by 25% and leaving the FSB where it is at did not produce a performance change. All of this indicates poor coding / config instead of a saturated FSB. Most likely a config issue as Obilivion + GTX280 SLI... I'm suspecting a driver issue here.

If it was an FSB related problem why does the AMD Phenom and its infamous HT also suffer of poor performance?

Thirdly at that resolution on a 680i motherboard... Well now theres a problem. My Q6600 @ 3.4ghz + 8800GT SLI general speaking produced a worse experience than my X38 + Q6600 @ 3.2ghz + a single 8800GT. This is more of a motherboard than FSB issue in my opinion.

Poeple must either post more complete details or not post anything at all. I play with a Q6600 @ 400x8, 4gb RAM and a 8800GT @ 1280x1024(my monitors max), max details, max viewing distance (this is a real killler, not max detail), AAx4 and AFx16. I get 40-50fps most of the time unless I'm viewing a area with 100+ objects such as a mountain side with hundreds of grass and tree objects. Surely if a 1066mhz FSB can bearly handle being in town then my 1600mhz FSB should die on most scenes with heavy grass/trees and many objects?

 

[kassler]

3. The FSB actually was the bottleneck.

Oh ****! you don't say

How hard can it be to understand that the FSB is a problem on Intel motherboards

 

[cjl]

How like you Kassler. You take what he said, and completely misinterpret it.

 

[spuddyt]

Kassler, you would love to meet this guy, he's called thunderman, and he continually goes on about how great AMD CPUs are and how the FSB is a bottleneck despite the fact that intel CPUs do better in most benchmarks... or wait, are you him?

 

[kassler]

Kassler, you would love to meet this guy, he's called thunderman, and he continually goes on about how great AMD CPUs are and how the FSB is a bottleneck despite the fact that intel CPUs do better in most benchmarks... or wait, are you him?

hahaha, where is Self-criticism

The REAL problem is that there are some people that have problems to understand that Intel isn't best on everything. I find it rather amusing to see how long they can go to explain their feelings about Intel and how hard it is for them to understand technology.

 

[JDocs]

Kassler, most of us here will admit that the FSB is a limiting factor for Intel in certain aspect but we are talking about if the FSB is responsible for the problem the original poster claims it is. That is however doubtful otherwise AMD chips with HT wouldn't be as badly effect.

The original poster is claiming its the FSB when it clearly is not.