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BUS vs MEM bandwidth: Lower means bottleneck?

Tags:
  • Graphics Cards
  • Bus
  • Bandwidth
  • PCI
  • Graphics
Last response: in Graphics Cards
July 27, 2004 2:41:30 PM

i am not sure if i used the right two comparisons, but i found out that in my new comp that my parents bought without my consulting, the mobo doesn't come with an agp slot.

So my question is, on a pci slot peak(not sharing)bandwidth is 132MB/S.(side question: if i am sharing with integrated network and sound, the bandwidth does divide for all three right?)

The mem peak bandwidth on my vid is 8000MB/s

Does this mean the pci bandwidth will lag the performance of my games for this reason,that it can't process the same amount of data in the same amount of time?

If i am totaly off, which i think i am, which two comparisons can i make (with one being the Pci's bandwidth)to find out what is the bottleneck.

More about : bus mem bandwidth lower means bottleneck

July 27, 2004 5:25:58 PM

any new computer bought after 2000 has an agp slot. look again :) 
Anonymous
a b U Graphics card
July 27, 2004 6:30:50 PM

you should know that HP or whatever can be a bitch about that. I saw new computer without AGP in 2004!

And yes the whole PCI bus is shared its parrallel...
Thats the beauty of PCIe its all serial.

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July 27, 2004 6:39:06 PM

Read a few white papers like

http://www.dell.com/downloads/global/vectors/2003_agp8x...

More can be found by google search. Most are from INTEL, so you can find it on intel website also.

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a b U Graphics card
July 27, 2004 6:44:44 PM

Totally untrue. The el-cheapo's have integrated AGP graphics (that suck) but not AGP slot for video card upgrades. Adding a PCI video card is a waste of money. IMO buying those Dell value series etc. is also a waste of money, yet people do it. What kills me is Dell sells these el-crappo's with Windows XP and 128MB of shared system memory. Ugh. 128MB shared with the AGP and running Windows XP... great combo. :mad: 


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July 27, 2004 10:23:34 PM

Forget that man. PCI slots have Half the speed of AGP slot. That machine uses the integrated AGP slot and is getting the agp speed. Getting a PCI graphics card will not improve crap.

Memory bandwidth is only as good as the slot you got it plug it to.

Wether it is integrated or is irelevant, it is still tying up a channel in the specific bus. Cannot believe that OEMs still put poeple through integrated sound or graphics. Gives me chills everytime I think of it.

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July 27, 2004 10:26:42 PM

Understand this... the PCI bus is not the same as the bus from the southbridge to the northbridge. The built in sound and ethernet are not taking away from your PCI bandwidth.

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July 28, 2004 3:53:50 PM

OK good, i was thinking about getting the geforce fx 5200 pci, the specs weren't horrible and i was going to OC it anyway.

"Understand this... the PCI bus is not the same as the bus from the southbridge to the northbridge. The built in sound and ethernet are not taking away from your PCI bandwidth."

This means all 133mb/s will be used towards the graphics card because I have no other pci hardware installed.

Now what does the pci 133mb/s come out to compared with the agp 8x 2133mb/s bandwidth?

Some of you say don't bother getting the pci v-card but i can't play BF1942 or NFS:U and online i loose to races because my FPS us too low, so my whole car is slow in comparison to other players. I'd rather get the card then have this piece of junk integrated crap.
July 28, 2004 5:36:34 PM

As stated before that is totally incorrect. The AGP bus may be there, but cutting out the slot saves costs.

These computers were not designed to be gaming PCs, integrated video is fine for MS office.

If you buy a PCI card, you are at least freeing up whatever system ram was shared with the onboard video.

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July 29, 2004 3:21:23 PM

I'd be freeing up maximum 64mb just because Intel has this technology that graps what it needs, when it needs it and min 16mb.

But that doesn't answer my question about the 133mb/s and the 2100mb/s.

BTW I've been looking at some pics involving the northbridge and southbridge and notice that pci is connected to southbridge. http://www.intel.com/design/chipsets/848P/pix/848P_sche...

So my new questions are what's the bandwidth between the north and southbridge? and what kind of data(size too)flows through there? (like say from the mem to the pci video card)
July 29, 2004 3:43:41 PM

Untruest:

I dont know if they bought this PC for you to use only but if they did and If it were me i would refuse to use the piece of crap, when they ask you why you arent using it tell them its because it wont do a damn thing you need it to do, and its worthless, thats what i would say, although im sure i would try and do it in a way that was a little more diplomatic eheh
July 29, 2004 7:21:55 PM

LOL, They bought it and i tryed returning it but we can;t. The salesman sucked them right in with this and that which is truly nothing.

Yeah but anyway back to my 3 unanswered questions.
July 31, 2004 3:42:56 AM

Sorry for the double post but my thread is fading away but i can guarante you that my questions aren't fading away.
July 31, 2004 7:36:59 AM

Quote:
OK good, i was thinking about getting the geforce fx 5200 pci, the specs weren't horrible and i was going to OC it anyway.

"Understand this... the PCI bus is not the same as the bus from the southbridge to the northbridge. The built in sound and ethernet are not taking away from your PCI bandwidth."

This means all 133mb/s will be used towards the graphics card because I have no other pci hardware installed.

Now what does the pci 133mb/s come out to compared with the agp 8x 2133mb/s bandwidth?

Some of you say don't bother getting the pci v-card but i can't play BF1942 or NFS:U and online i loose to races because my FPS us too low, so my whole car is slow in comparison to other players. I'd rather get the card then have this piece of junk integrated crap.

OK.


yes, if you are not using any other PCI devices, then if your video card needs it it will get the full 133mb/sec bandwidth.


the 133mb/sec compared to 2100mb/sec isnt that big if a deal wiht a FX5200, i believe there was a PCI Video card reveiw floating around months ago that showed PCI cards performing suprisingly well. AND, if your FX5200 has 128megs of video ram, thats even better because that means less data will have to be swapped along the 133mb/sec PCI bus, it can just sit in that nice fast video ram.


you said you cant return the computer. so i think a FX5200 will DEFINATLY help you in gaming.. it wont be pretty, but at least it will be Playable.


Quote:
So my new questions are what's the bandwidth between the north and southbridge? and what kind of data(size too)flows through there? (like say from the mem to the pci video card)


i cant be bothered to look it up , because different motherboards have different "links" between the north and south bridge. and it doesnt matter whatsoever to you , its not a bottleneck

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July 31, 2004 7:41:57 AM

Quote:
The built in sound and ethernet are not taking away from your PCI bandwidth.


as far as i know, most motherboards (except specific very new ones) have the ethernet controller, ide hard drives, and sound (among other things) residing on the PCI bus

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July 31, 2004 7:44:02 AM

Quote:
Forget that man. PCI slots have Half the speed of AGP slot. That machine uses the integrated AGP slot and is getting the agp speed. Getting a PCI graphics card will not improve crap.

totally UNTRUE.


the integrated video maybe sitting on the AGP bus with that nice bandwidth, but the chipset itself just is not powerful enough for gaming. a 9100 PCI or FX5200 PCI will TOTALLY OWN11111 any integrated video that this guy could possibly have, beacuse the video chip itself is quite powerful. its like comparing a TNT1 to a Geforce3, they are both AGP4x, but you can give that TNT1 all the bandwidth you want but theres no way it can even come relatively close the Geforce3.

once the data is loaded into the PCI video cards ram, the only real lag will come when that ram runs out and new stuff needs to be loaded . as i said if he has a 128meg PCI video card, this wont be much of a problem at all



PLUS you have to consider what kinda ram the integrated video has. it uses slow system ram. sure, it may have 8xagp link to the northbridge, but ALL THE DATA has to be contantly transfered across this. a video card with dedicated vidoe memory wont suffer from this , and its own internal bandwidth will be much higher (i think he said the FX5200's memory bandwidwth would be 8gb/sec)
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July 31, 2004 8:05:47 AM

Fukc all of you guy's.
He's stuck with the PC, and he's stuck with add-on PCI graphics.
His best choices are = Radeon 9100PCI, or GeForce FX5600PCI.
He's still a n00b, so these cards might display breathtaking results for him :lol: 


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August 3, 2004 5:29:19 PM

Thanks guys, i was away for the weekend, so i couldn't answer back but phial you've been a great help clarifying up some stuff and some stupid things i haven't thought about my self. I was thinking that having 128 mb on board would say that most of the data would stay on board and not even require to be written to the system ram. I think that's what i'll do and buy it.

As for a noob, i may be new to this forum, but i've been reading for years and giving out tips of my own. But whatever it's just a name lolz

Thanks again guys, i am going to check if that 5600 pci actually does exist