4x vs 8x AGP performance comparison

[dfgasner]

My dad just got a x850xt pe and just realized that his box doesn't support 8x AGP and only 4x AGP. He was just wondering what kind of performance impact this is going to make.

Here are his specs:

P4 2.56Ghz 533Mhz
Asus P4B533 Mobo
(2 x 512MB) PC2700
VisionTek X850XT PE AGP
Creative Audigy Platnum

3DMark05 = 4100

I know that this has probably been discussed before and I've looked and can't seem to find what I'm looking for.

Thanks
Davey

[sia]

It will decrease frame rate on heavy 3D graphics like games and 3D modeling programs. I think 4x is good enough for all 2D tasks like windows appearance and movie editing.

[ski]

You may want to read the following article that I found on another site before installing the new card:

<<Will my 8X AGP video card work in my 4x AGP slot?

This question is not answered as easily as it might seem.
First let's establish a few things you need to know to answer this question.

What is AGP 2.0?
AGP 2.0 is a 1.5V AGP slot capable of 4x,2x and 1x speeds.

What is AGP 3.0?
AGP 3.0 is keyed like a 1.5V AGP 2.0 slot, but it only uses 0.8V of power. It supports 8X, 4X, 2X and 1X speeds.

Rule #1: Speeds are backwards compatible-
AGP Speeds are required to be backwards compatible. This means that an 8X video card MUST be able to run at 4x, 2x, or 1x speeds. However, this does NOT necessarily mean that your 8X card will run on a 4x slot.

Signalling Voltage incompatibility-
Because speeds must be backwards compatible, 'Signalling Voltage' is where incompatibilities arise. Basically, all 8x cards are 0.8v AGP 3.0 spec 8x cards will fit in 1.5V slots, and can tolerate the voltage, but will NOT run properly.
4x cards can be either 1.5V or 0.8V.
2x and 1x cards are either 3.3V or 1.5V.
Except in the case of the 8X cards, using the wrong voltage card with the wrong motherboard can result in damage in card and board.
If you install a card of incompatible voltages with the motherboard's specs, the card will NOT run.

The connectors on AGP video cards are keyed in such a way that you can only install equipment that have compatible voltage keyed connectors. Normally the key of the card determines its signal voltage. AGP 1.0 and AGP 2.0 cards using a 1.5V key will signal at 1.5 volts. However, AGP 3.0 devices can tolerate 1.5V - they won't be destroyed, they just might not work properly.

The bottomline is that your 8X video card can theoretically be safely TESTED in any 1.5V motherboard for compatibility. But if you know for a fact that your board only runs 1.5V AGP 2.0 spec and your 8X AGP 3.0 card runs only 0.8v spec, then the two should NOT be compatible.
At the very least it will be unstable, if it runs at all. However, we've had a lot of users tell us that their AGP 8x cards work on 4x only motherboards. This is likely due to the fact that some AGP 8X video cards are in fact universal 1.5V capable AGP3.0 cards that can run on either 1.5V or 0.8V (remember, AGP speeds are backwards compatible, only voltage incompatibilies cause problems).>>

[hockey man]

For a slighly larger budget, or for PC's with lower wattage PSU's (ran into that recently), the GeForce FX 5200 is a good choice. Costs around $50-70, it can be 4x or 8x/4x. 64MB, 128MB, or even 256MB of DDR RAM, 64-bit or 128-bit, generally around 3-6.4 GB/s of RAM bandwidth. 2 x 2 pipes, DX9-class (technically), core speed of around 250MHz. Not really able to run DX9 games like Doom 3 or HL2, but it's a decent performer for older games. You could possibly play HL2 in DX8-mode, but this thing doesn't have a lot of power behind it.

For a good performer that is usually 4x compatible, the Radeon 9600 Pro/XT is my choice. Last time I checked, the XT could be found on Newegg for about $90-100. 128MB or 256MB of DDR RAM, though I would recommend the 128MB versions, 128-bits, generally around 9.6 GB/s of RAM bandwidth. 4 pipes, DX9-class (barely), core speed of 400-500MHz. Able to play Doom 3 and HL2 at the lowest settings, and other games like WarCraft 3 at medium/high settings.

For performance-minded 4x gamers, the Radeon 9800 series is good. Generally in the $110-140 range (last time I checked) it's important to pick these out carefully for true 4x compatibility. 128MB or 256MB of DDR RAM, 256-bits, generally around 20-24 GB/s of RAM bandwidth. 8 pipes, DX9-class, core speed of 325-380MHz. Able to play Doom 3 and HL2 at around 800 x 600 with medium details, and can handle pretty much any sub-DX9 game out there.

That is what the great Hardware god suggests.

[saphalline]

If I'm reading the original question correctly, your dad already has the X850 XT PE in the system working fine, right? And if I remember correctly, the Asus P5B533 used the i845PE chipset, right? Being that the vid card is already working, I'd say it's fine!

In terms of 4x vs 8x performance, you probably won't notice it on a system like that. You'd need a P4 3.0GHz or faster with 1GB of dual-channel PC3200 before you'd notice a difference between 4x and 8x. And if you had that kind of hardware, you'd be running in 8x mode, anyway.

I say don't worry about it. If it's installed and working fine, just let it go.

[dfgasner]

K thanks a lot.
Yea the system is working fine and it's awesome.

I didn't think that there wasn't going to be much of a performance decrease.
He doesn't care he can play anything he wants all out.

About the 0.8 V and the 1.5 V IDK because inside the system details of 3DMark'05 it says that the card is running at 3.3 V, but I just figured that that was because of the external power.

Thanks a lot for your word of wisdom

Davey