.8V AGP 和 1.5V AGP

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What is 1.5V AGP and .8V AGP?
By Lee Penrod

The title of this article is currently one of the most asked questions of our sales department. This article will take a look at this issue and educate you about the topic.

    * Who needs a 1.5V AGP card?
    * What cards are 1.5V?
    * Is my AGP card 1.5V?
    * Isn't AGP backwards compatible?
    * What is .8V AGP?

Who needs a 1.5V AGP card?

1.5V AGP cards have increasingly become a requirement of new motherboards/chipsets. If a motherboard requires a 1.5V AGP card and you place a AGP card in it that is not 1.5V, you will physically damage the motherboard and probably the video card as well. The following chipsets are known to require 1.5V AGP.

    * Intel
         1. i845-all versions/variants
         2. i850-all versions/variants
         3. i850E-all
         4. sis-all for P4
    * AMD
         1. All Force chipsets including 220D,220,420,420D,415,415D

As a rule of thumb it is best to use a 1.5V AGP card with a new motherboard if there is any doubt.(Especially true for Intel based systems P4 and above.)

What cards are 1.5V AGP?

The good news is that almost all 4x AGP cards support 1.5V. For convenience here is a rough list of graphic card types that are almost always compatible.

    * Geforce2, Geforce2 MX, Geforce2 MX200/MX400
    * Geforce2 ultra/Pro/GTS/Ti
    * Geforce3/Ti200/Ti500
    * Geforce4-ALL
    * ATI Radeon DDR
    * ATI Radeon 7000/7200/7500/8500/8500LE/9000/9500/9700
    * ATI ALL-IN-WONDER Radeon/ALL

Please note that this list is not all inclusive. If you are wondering if a certain card is compatible and is older than those listed above please see the next section.
Is my AGP card 1.5V?

Luckily there is a easy way to distinguish a 1.5V card from a non-1.5V card. The bottom of the connector that goes into the AGP slot is keyed differently. An incompatible card will look like the picture below:

Notice that the bottom connector has only one notch. A compatible card will have a connector like the one below:


Most motherboards that can only use 1.5 volt have a slot that is incompatible with the older single notched connector - however, there may be exceptions to this rule so check before trying to insert a new card. Inexperienced system builders have been known to force the wrong AGP card into a 1.5V slot often with disastrous results!
Isn't AGP backwards compatible?

Yes, and No. Older 2X AGP cards do not use the right voltage to function properly in the newer 1.5V AGP slots. If forced into a 1.5V AGP slot, a non-1.5V compliant video card will damage the motherboard. On the other hand a 1.5V AGP card is usually backwards compatible with older 2X AGP slots.
What is .8V AGP?
.8V is the voltage requirement of new 8x AGP cards utilizing AGP specification 3.0. Motherboards supporting 8x AGP support both 1.5V AGP 2.0 compliant cards (AGP 4x) and newer .8V AGP 3.0 compliant cards (AGP 8x). The keying for AGP 3.0 cards is identical to that of AGP 2.0 cards to retain backward compatibility. A motherboard that supports 8x AGP should work fine with a 1.5V (AGP 4x video card), and a motherboard that supports 1.5V (AGP 4x) video cards should work ok with a .8V video card (AGP 8x), however in the later example the video card would only work at the fastest speed the motherboard supports (AGP 4x).

Directron.com is not responsible for any damage or problem as a result of following the instructions outlined in this manual. Do it at your own risk.

Last Updated: 4/25/03

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