via or i815?

[neo_otyugh]

i have a p3500e that is needing a home...i am torn between the newer via chipset boards and the asus cuvx4. i am looking for a board with agp, 1 isa, prefer ata 100 (66 will do...in a pinch), would like to avoid onbaord anything. i also want bios overclocking. it would be for a gaming rig mostly...
the things that i am not crazy about is lower memory cap of the i815, i am concerned with its compatibility with the variety of ram available now. i want to eb able to buy cheaper ram and not worry about compatability. also the i815 seems to be hard to find with ISA support. and with the via chipset it seems to be harder to find ata100 capable boards.
would love to hear experiences and advice on what to get...

[Peter M]

Problems with 815:

Limited SDRAM compatibility.
AGP aperture size limitation, choking high-end games.
No ISA bridge in chipset, requiring an extra PCI-to-ISA bridge chip that costs money ... making i815 boards even more expensive than they already are.

VIA's current chipset combination of 694X/Z north and 686A south bridge, "Apollo Pro 133A", doesn't have these limitations ... and is just being upgraded to use the 686B, bringing UDMA100 IDE. There's no integrated graphics unit though, but if you're stabbing for performance, you won't be using that anyway.

Regards, Peter

[neo_otyugh]

thank you...you once again impress me with a very precise answer to a vague question. you have the knack of answering what i ask when i am not totally sure exactly what i am asking.

plus i had no idea it had the agp aperature limitations, but did suspect that ISA compatability had been removed...

[This message has been edited by neo_otyugh (edited 11-08-2000).]

[Peter M]

You're welcome.

ISA is on its way out in general. VIA's next iteration, by means of their 8231 south bridge chip, will also ditch it. SiS' latest all-in-one chips have no ISA, Intel's 8xx chipsets also don't. ALi's latest south bridge series 1535 join the club.

The contact pins/balls that have been sort of wasted for ISA bus output now are used for more modern features like loads of USB ports, integrated LAN function, and more neat stuff.

Regards, Peter

[neo_otyugh]

I would like to mov away from ISA altogehter but for now I like having the option of one slot. I know this will be the last board that i need that supports ISA.


The new Via southbridge you mentioned...the 686b...when is it slated for release? i tried a search of the via site but had no luck there...

[Peter M]

It's available right now. Boards having it are already shipping (at least here in Germany, the DFI AK74EC is in the shops - that's an Athlon board, but uses the same 686B south).

Regards, Peter

[canit]

Are the 686a and 686b the same chipset just programmed differently? Could you take a socket A board with 686a and flash the bios with a later generation 686b bios to gain UDMA 100 etc?

[neo_otyugh]

found one on the dfi website...looks like i may be getting a dfi board now http://sysopt.earthweb.com/forum/smile.gif

[neo_otyugh]

argh it doesnt seem as if the CA64-EN or CA64-E is sol din the US yet...

[Peter M]

No. The 686B is a new revision of the hardware, with the added capability to do UDMA100. Of course this needs BIOS and driver support, but it won't miraculously add UDMA100 to a 686A. (If this were possible, VIA wouldn't have bothered revising the chip ...)

The other way round, use a 686B with a BIOS or a driver that isn't 686B-aware, and you'll lose UDMA100 but be fine otherwise.

Finally, most board vendors code their BIOSes to be compatible with either, so those people having the older board revisions with the 686A aren't cut off later BIOS developments.

Regards, Peter

[neo_otyugh]

the aopen AX34 Pro II looks to be a good board also, hoping to still find the DFI with the 686B...it seems that dfi has more affordable prices in general...
thanks again Peter for the heads up on the new via chipset

[This message has been edited by neo_otyugh (edited 11-09-2000).]

[canit]

Thanks for the explanation. So the Asus A7V(UDMA 100) has been using the Promise onboard controller to achieve UDMA 100 not the southbridge.

[Peter M]

Exactly. Those boards that have been offering UDMA100 before did so by means of an extra PCI device. The benefit is, you get four IDE channels (and board makers can still choose to use the updated 686B for four UDMA100 channels).

The other side is cost. Of course, the controller chip costs money, and then you lose one PCI bus master position, so you have to add another piece of silicon to still be able to offer fully capable PCI slots.

Regards, Peter