Lots of PCI solutions - why did no one create a PCI+AGP solution?

[B00tDisk]

Just curious.  Anyone know why?  Was it bus bandwidth limitations on the Amiga side? Was it viewed as overkill?  Too expensive?  Certainly now with the Pegasos and A1 systems going forth it's a bit redundant, but I'd always wondered why no manufacturer took the next logical step and included AGP on the various busboards for the 1200, 4000 and 3000.  

[csirac_]

1) Data rates. Peak/burst bandwidth of PCI was around 266MB/sec... it's supposed to sustain 133MB/sec (though many implimentations do less, around 100MB/sec). Whacking a PCI bus on a 10 year old PC only serves to allow upgrade options, not performance. You're not going to get 100MB/sec transfer speeds between the Amiga's CPU and a PCI device (though you may get this _between_ PCI devices on the PCI bus if the host controller/devices involved support it).

2) Practical issues. At the time Amiga PCI expansions were being released, you could mostly get PCI versions of most video cards.  (considering the age of our Amigas, you can still get pretty decent PCI cards even now - A TNT2 is still waaay faster than my CGFX64/3D). And since AGP 1x was basically PCI rewired a bit (some of the early AGP intel chipsets actually had a pin you could set that could make it's AGP bus be another PCI bus), it wouldn't have made much sense to have an AGP slot.

3) Speed, again. From (1) we're flat out justifying PCI, let alone AGP 2x or higher. From (2) we can see that initially, AGP was not actually a *faster* bus per se, it's just that it was a dedicated one. It allowed a dedicated data path to the CPU without competing for cycles with your NIC, RAID, sound, IDE, USB, etc. From a technical point of view, it simply doesn't make sense to defeat the whole purpose of AGP by putting it back on the PCI bus where we started :-)

So nowadays, the only point of putting an AGP bus on old A4000 would be to allow us to use new cheap video cards at 0.0001% of their capacity... and who knows, maybe someone will do that, it's just as crazy as putting PCI in ;-)

Cheers,

- Paul

[DoomMaster]

- Trolling: edited by mikeymike -

[Piru]

[edit: no need to feed the troll]

[Karlos]

One reason why an AGP slot may be a good idea is the basic availability of the hardware.

Performance issues aside (we all know no 68K system is going to push AGP data rates over the bus), there seems to be far more choice in the AGP card market than the PCI one.

Having said that, however, we don't yet have drivers for all the PCI cards out there, let alone AGP ones ;-)

[lempkee]

yeah it would be amazing with a 7.2 megs per sec memory bandwidth

seriously we dont need agp on our amiga , besides an agp board has allready been made ? , and its called  "sharkppc+" , this one should give great performance unlike mediators etc, why?  well because of the fact that its a own motherboard who only talks to the main amigamotherboard when it needs to (sounds weird ) , so if and when that come , well there u go...agp in your amiga.

dont confuse this with sharkppc which is just a pci g3/g4 card., the + model has more stuff so.

anyway if u knew how slow the pci stuff on amiga is atm , well then you wouldnt ask of this atm i guess , but then again everything is better when its an pci/agp standard, ie you could get cheap hardware without looking for months/years.

mediators on a4000 gives about 14-20 megs a sec and a1200's about 6-9 megs per sec, sounds little ? ,well remeber its a hack and remeber it feels fast as hell compared to zorro2/iv hacks that has been made etc , so it was a good start.

the agp would be slower if it was just slammed a agp bus on a mediator, a sharkppc+ would be much faster and i think you should get +50megs a sec without a prob (pegasos is only 70-75 in write speed per sec) (amigaone higher though not too much higher).


i hope this helped and didnt confuse ya totally.

i aint against hw ugrades at all, but somewhere must the limit go.... i want a sharkppc and + btw


pps: atari falcon came with pci first , now they also have agp

cheers

[Karlos]

@lempkee

Not all amiga PCI systems are created equal. A while ago I gathered a fair bit of information on direct gfx access speeds for current amiga gfx cards. 7.2M/s was probably the slowest.

The fastest results I got back tipped 35Mb/s...

[Cyberus]

@lempkee

i want a sharkppc and + btw

Me too! Iimagine having an A4000 with that much power...

The Shark ppc+  has a fast IDE controller

[Karlos]

Yeah :-D

Whats the current story with the sharkppc+ anyways?

[downix]

No 68k northbridges with AGP.  

[Karlos]

@downix,

Well I guess that answers that :lol:

[Cyberus]

 :lol:

[lempkee]

current information about sharkppc is as allways.

ITS DeLAYED..still prototype for sharkppc (the one we saw in 2000) (and i held one) , not working though...or better...not in use.

about Sharkppc+ (the entire board) (with agp  which u hook up on the mediator, well no prototypes shown of it, no pictures etc , so either is vapor or the polish goverment has taken over the job

anyway elbox says this:

sharkppc will be released when os4 comes .

then 2 years later. (last week)

Sharkppc will be released in december 2003.


and hyperion says. (a while back)

We dont have the hw to make os4 work with, we dont know anything about the cards , except for the stuff they claim it has (or something like that) .


sadly no quotes here but its as near as i could get it (to the proper text) ,

EITHER this is a conspiracy , or its just another boxer/abox etc... surely elbox has to do that "amiga" mistake also...

cheers