PCI-Express Is X8 too slow?

Gaucherre

Junior Member
May 22, 2002
8
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Recently I saw a motherboard/cpu combo deal that looked like a very good deal. Motherboard has integrated nvidia 6100 graphics chip plus a pci-x upgrade slot. Checked reviews of the motherboard which were good except fpr one spec. The pci-express X16 graphics slot is enabled at X8, not X16. Assumed that would cripple a good graphics card and therefore disregarded that board. However, now a local system builder/enthusiast (but not an engineer!) says don't worry, the X8 is fine, plenty of bandwidth in those 8 "lanes" for current graphics cards. If I built a new computer using this board I would want an nvidia 8800gt card, and there would be no further upgrade for the life of that computer. And no overclocking would be involved, either.

So, is X8 enough for good graphics performance or am I crippling a good graphics card with a serious limitation?

Regards
 

adlep

Diamond Member
Mar 25, 2001
5,287
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x8 will not be a problem for at least next 2-3 years. The raw bandwidth provided by the x8 PCIE bus is still twice as fast as the AGP 8X...

 

chizow

Diamond Member
Jun 26, 2001
9,537
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Should be fine with X8 with current GPUs. I wouldn't expect any bottlenecks for at least a few generations. X1 is certainly a problem, as some guy recently had about 50% performance from his 8800GT because the mobo kept defaulting to X1. There was also a review of a high-end Gateway system sometime back where there was a small performance hit (maybe 5%?) when an 8800GTX was run in the 2nd X4 PCI-E slot. Chances are you'll outgrow the mobo before you run into any PCI-E bottlenecks.
 

taltamir

Lifer
Mar 21, 2004
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it wouldn't kill your performance... but you would probably get a few more percents by using a full 16x board... Why are you even getting a board with integrated graphics if you plan on buying a 8800GT? or do you already own that board and want an upgrade? if so don't worry about it, the board should be enough. Not maxing out, but no crippling either.
 

Gaucherre

Junior Member
May 22, 2002
8
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Integrated graphics is coincidental. Just saw a combo deal for board & cpu that is same price as cpu costs by itself.

Speaking of good deals, what is the cheapest SLI motherboard that's any good? Something that would give me an option to upgrade with a second 8800gt later on.
 

taltamir

Lifer
Mar 21, 2004
13,576
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dont. Its never worth it . SLI is not for upgrades, its for more performance now... there is ALWAYS a better card for less money by the time you get around to upgrading...
 

hans007

Lifer
Feb 1, 2000
20,212
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x8 shows some performance degradation with really high end cards like say 8800gtx or 8800gt.

some really cheap nvidia igp chipsets (6100-405) only have an x8 slot that is x16 physically and there have been benchmarks done online that support that it slows down just a little on a really high end card.
 

taltamir

Lifer
Mar 21, 2004
13,576
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Some degradation is par from the course... the real question is... is it "ZOMG I will be an idiot to do this, its throwing money into the fire" or is it "well, the extra performance I would get from 16x vs 8x does not justify upgrading my motherboard".

I have to say btw, That I am merely estimating that 8x would fall into the second category. I am not certain of it though.