Help! Radeon 8500LE only works in AGP 2X mode!

jiffylube1024

Diamond Member
Feb 17, 2002
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I picked up a Radeon 8500LE 128MB (retail, built by ATI) from Best Buy in Mississauga yesterday (a Canadian hot deal, is this a first?), and had some trouble getting it hooked up at first. I installed it in my home PC to test it out before it goes into my main machine at school. Being lazy, I simply uninstalled the drivers of the GeForce 3 that was in there, and put in the newest ATI drivers from Rage3d.com ... the machine would crash within seconds of any 3d game - fear of the infinite loop bug washed over me like a flash flood hitting a hillside village. However, being the computer geek that I am, I merely searched some forums, and found a plethora of suggestions for getting Radeon 8500 cards to work, many of which didn't work for most people but I decided to give it a shot anyways.

So, I went into my BIOS and disabled everything extra in AGP: fast-writes, side-bands, etc. and finally had to lower it down to AGP 2X mode. I have run it for about 3 hours now with zero problems with both the drivers that came with the card (I forget the version #) and the 6166 drivers. I overclocked the card to Radeon 8500 levels (275/275) and have zero problems whatsoever. I also get a nicer 3dmark 2k1SE score and better UT2k3 speed with this card. I really like this card, as I was looking for a 128MB card with similar performance to my GF3 to handle newer games large texture sizes. However, I am concerned that I have to run it on AGP 2X - I know that there is no performance difference, but why does it have to be so? Every nVidia card I have ran runs with all of the goodies on on all of my machines: fast-writes, AGP 4X, etc ... I'm not going to test this card on this machine any further as I am going to school very soon and installing it on my P4; I'll check back here to see if anyone has any suggestions for this machine for why I have to turn off these AGP features in the BIOS on this machine.

This is the machine I am testing this on:

Athlon XP 1800+
Epox 8K-7A motherboard (AMD 761)
256MB Crucial DDR
350W generic PS
15GB Seagate HD

I am interested because I might want to get another 8500LE for this machine down the road.

Any suggestions would be great.
 

cgs007

Member
Jul 31, 2002
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Hey jiffylube we must be neighbors cause i picked one up at the best buy in mississauga too for $149 and had the same problem on 2 machines i tested, so i took it back and got another figuring it must be a overheating problem(crappy fan on the ati built ones)
Anyway the second one didnt crash out in ut2k3demo but i did disable all the agp options in the bios.
BTW what AGP Aperture value is it set at? mine is 64meg and i dont know if i should raise or lower this value?
I cant answer your 2x question but wouldnt you figure running at 4x would perform better?
 

Moishe

Member
Feb 27, 2002
108
2
81
I'm by no means an expert, but AGP speeds only make a difference when your card runs out of space and uses system ram via the AGP bus.
So, if you've got a 128mb card, this shouldn't happen often. other than that, my understanding is that there is no difference between the different agp modes. it may be that there is a bus mhz difference, but I dunno.

The agp aperture size, in my understanding, sets the max amount of system ram that you want to allow your video card to use (if it needs it).
AGP is great for built in video where they have "shared" 8mb or something of the sort. That way manufacturers don't have to add ram to the board. It's bad for gaming though as access to system ram is much much slower than access to ram on the card. my understanding is that 8x AGP simply has 8 times the bandwidth to the system ram. With 8x being 8 times faster than 1x.

I have no idea what fast writes and the other stuff is for... anyone who knows care to explain???

mo
 

Shah4u

Junior Member
Sep 15, 2002
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First about AGP fastwrite and sideband adressing

AGP Sideband Adressing

It`s a technique to transfer Cpu instructions for the required for the game from cpu to the AGP Chipset and to card.AGP side band is you can say that crippled version of AGP Fastwrite.Data is Transfered through the AGP Bus while the CPU instructions to the GPU is given to the GPU through A Band Called Sideband.IT helps to in crease the performance When running the System in AGP 1.0 Mode.

AGP Fastwrite

AGP Fastwrite is now very commen in new cards from the age of AGP 2.0 and 4X AGP cards like geforce.
It was first implemented in nvidia Geforce.Back in the days of Intel BX boards and AGP 1.0 the AGP chipset on the board first took data from the CPU then it transfer data to system the memory(which is very slow indeed as compared to the Gpu`s memory).Then it take back the required data from the memory and then transfer data in AGP 2X mode to the Gpu.The draw back of this was that it takes alot of time to transfer data from cpu to gpu.
So a technique called AGP Fastwrite was made to transfer data from cpu to gpu directly through AGP Chipset.Now when you enables the Fastwrite ur Chipset takes data directly from Cpu and Gave it to Gpu so it saves a lot of time for the data wondering around in the Mainboard and latest games which reqiures a heavy cpu usage runs a little bit faster.
Note:AGP fast write can only be enabled in AGP 4X mode so it tranfer data at a speed of 1 Gb/sec approximatly.

AGP 1.0

CPU(512MB/sec)-------AGP Chipset(100Mhz bus)-------Ram(100MHZ bus)------AGPchipset(512Mb/sec through sideband(+128MB/sec for Cpu Instructions)------GPU

AGP 2.0

CPU(1024MB/sec)--------AGP Chipset(1024MB/sec through side band and 4GB adressing)--------GPU

See for yourself the difference AGP 1.0 and AGP 2.0
That why the difference When u enables the 4X mode,Side bandadressing and fastwrite(AGP 2.0 Specifications) ur GPU `s output will be 20-30% faster than when u disable the fastwrite,sideband and 4X mode and goes to the 2X mode or AGP 1.0 Specifications.

As these new GPU`s runs really very fast so u don`t see but when you enable these options in the Bios
run 3DMark 2001 and see the diffrence for urself.Ur Points will increase a lot.

Well I have explained a lot to u Guys if u wanna Know Any thing More Plz mail me AT

goforshah@hotmail.com

I will Appretiate any help needed.

PS:(Don`t forget to enable 1:AGP Fastwrite,2:Sideband Adressing,3:AGP 4X Mode) :p
 

Moishe

Member
Feb 27, 2002
108
2
81
Good info.
So what's wrong with his card? is there a history of 8500's not running at AGP4x?
Anyone ever run into this problem?
 

cgs007

Member
Jul 31, 2002
78
0
0

I'm not sure but i have loaded all the latest Via drivers > ATI drivers and all windows updates for 98 SE, it has crashed once since i changed AGP to 2x , the other card would crash out my system after 2 mins into a game.
BTW the same system with a gf2 mx and radeon 7500 installed ran smooth, no lockups but the 8500 is a faster card so maybe it's an overheating problem?
 

jiffylube1024

Diamond Member
Feb 17, 2002
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71
hey there time to check back in. I have set up the card in my P4 and it runs great! AGP 4X works great on this one (I don't see fast writes, side band, etc in the BIOS but I assume they're on. I haven't run any checks yet to see if they are enabled or not... I don't really care either, because it's 100% stable, so there's no point to tinker right now...). I don't know what the problem was with the other one (AMD 761 chipset) , but like I said AGP 2X seemed to fix the problem on that one, and it got a 3dmark 2k1 score that seemed about right (~8500).

cgs007 - #1 I don't think it's a heat related issue because I have been running the card at 300/280 for awhile now - I got it up to about 310/310 without any artifacts, but backed it down because I want this card to last awhile ;). I've had zero stability problems, and this has 3.6 ns RAM! The default is 250/250 btw. I get a score of 9600 in 3dmark 2k1 with the Radeon at 300/280, by the way :). What a deal though on the cards, eh?

#2 No, I dont think going to AGP 4X would really make any difference in performance. It's great in 2X as it is, anyways!

#3 Edit: oh yeah and my AGP aperture size is 128MB on both machines. I usually set it to between 1/4 and 1/2 of my memory size. Typically it's 128MB. It really doesn't matter though - the whole point of cards with so much memory is so that they never have to access the memory by AGP (big time slowdown), so it's kind of a moot point!

I think the crashes are just an issue with the AMD 761 and probably on VIA chipsets also. I don't really know why they occur, but I can tell you that none of these problems occur on my P4. Really, though, there's not too much of a difference in performance.

 

cgs007

Member
Jul 31, 2002
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That was a good deal on those cards eh :) that's why im trying so hard to get it to run stable.
Anyway i think my problem was the PSU (too low @230 watts)
A few others told me i needed more juice because i actually underclocked the card a little (240x240) at it's rock solid now.
Even at that speed it still kills my radeon 7500 .
3d mark 2001 =5200 even with my old Duron 950 and measley 128 meg of ram
The system it's in now is temporary until i can build my next one ,so i will make sure i get a Good 400 Watt PSU for this card.
I also overclocked it to 300x300 and no artifacts either but it then crashes out when i play UT2K3 due to the power issue.

Cya round ...Chris
 

cgs007

Member
Jul 31, 2002
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BTW the Computer Show is happening at the EX this weekend from Friday-Sunday in case your like me and have the upgrade sickness !!
 

jiffylube1024

Diamond Member
Feb 17, 2002
7,430
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71
Originally posted by: cgs007
That was a good deal on those cards eh :) that's why im trying so hard to get it to run stable.
Anyway i think my problem was the PSU (too low @230 watts)
A few others told me i needed more juice because i actually underclocked the card a little (240x240) at it's rock solid now.
Even at that speed it still kills my radeon 7500 .
3d mark 2001 =5200 even with my old Duron 950 and measley 128 meg of ram
The system it's in now is temporary until i can build my next one ,so i will make sure i get a Good 400 Watt PSU for this card.
I also overclocked it to 300x300 and no artifacts either but it then crashes out when i play UT2K3 due to the power issue.

Cya round ...Chris
Yeah it sounds like a power issue - just get either an Enermax 350-400W PS or buy a new case with a 300 or 350W PS and you should be fine. Dang, I can't really go to the EX this weekend, I gotta study for 2 tests this week... d'oh!
 

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