# AGP 8x vs. PCI-E 16x



## Ruzzy (Oct 14, 2005)

Can i have a list of all known differences between AGP 8x and PCI-E 16x please?


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## UncleMacro (Jan 26, 2005)

AGP 8X can transfer data at about 2 GB/sec maximum. PCI-Express x16 can read at 4 GB/sec and simultaneously write at 4 GB/sec. Sometimes people call that 8 GB/sec although that's being charitable as it applies to video cards because almost all transfers to video cards are writes only. Only games stress the transfer rates to video cards and current games rarely show any performance gain when you have at least 1 GB/sec. So currently there is no noticeable performance difference in games between AGP and PCI-Express x16. Someday off in the future when everything else has sped up then PCI-Express will provide a speed advantage.

PCI-Express can supply more power through the slot than AGP slots (as I recall it's 75 watts versus about 45). As a result, AGP cards are more likely to require auxiliary power from a disk drive power cable.

You can have more than one PCI-Express x16 slot in a single motherboard (although the x16 part usually is cut down to x8) so you can use two (or more) PCI-Express x16 video cards in tandem to increase performance. AGP motherboards only have one AGP slot.

The best video cards coming out these days are for PCI-Express x16 only. People with AGP slots have slim pickings. So if you're getting a new machine then you should always get PCI-Express. It has a long future ahead of it whereas AGP is already winding down in terms of what kinds of video cards you can get for it.


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