Tonga does have a 384 bit memory bus - confirmed

Business reasons, eh.

I definitely wouldn't mind seeing some benches of a 285/380X on a 384bit bus.
 
Yeah... I can see why, how to Market this?

3GB people would've complained of low vram, 6GB people would've complained of price and not useful for this GPU except in Crossfire.

256-Bit at 4GB made sense.

Curious if they used the full 384 bit bus for Apple?
 
The m295x is a 256-bit configuration and technically a mobile GPU. A 384-bit mobile configuration would be problematic from a space perspective due the extra memory chips. I'm not aware of any 256-bit+ mobile GPU ever.
 
These things get designed pretty far in advance. I imagine they would have released the Radeon R9 380X with 3GB of RAM if that was still marketable, instead of the situation right now where < 4GB is "too little". Either that or it doesn't improve performance enough to justify the additional cost for the PCBs because they'd need to use thicker PCBs (more layers). A lot of chips ship with features that will never be used.
 
Quix said:
These things get designed pretty far in advance. I imagine they would have released the Radeon R9 380X with 3GB of RAM if that was still marketable, instead of the situation right now where < 4GB is "too little". Either that or it doesn't improve performance enough to justify the additional cost for the PCBs because they'd need to use thicker PCBs (more layers). A lot of chips ship with features that will never be used.
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^This..

384bit bus would be just too expensive for the price segment they wanted to push those cards, Tahiti were already a PITA to re-brand AIBs had to do a lot of tricks to cheap out in components and/or cooler to keep prices near AMD desires.. 384 bit is not only thicker but also more complex which mean more money, and also require more memory chips which are also more money involved. but also a fully unlocked tonga with 384 bit would have made it too close of 390 Performance due the updated GCN revision at a much lower price and power consumption.

Tonga is good, but those cards are starving bandwidth, GCN is bandwidth hungry, the 256bit choice is in my opinion a bad one, R9 285/380 its pointless with those 4GB. because at the end of the day they lack of processing power to fully utilize it in the demanding games, 3GB with higher bandwidth would be better. and the same apply to the 380X.
 
Are we really sure the new 380x is bandwidth starved? It seems pretty neck-in-neck with the 7970/280x on all the benches I've seen. And newer GDDR5 seems generally more readily overclockable than older stuff (no one is making lower-clocked chips anymore).

I don't remember seeing a bench where anyone has separated memory overclock from core overclock, so I do reserve the right to be wrong. :D
 
Derfnofred said:
Are we really sure the new 380x is bandwidth starved? It seems pretty neck-in-neck with the 7970/280x on all the benches I've seen. And newer GDDR5 seems generally more readily overclockable than older stuff (no one is making lower-clocked chips anymore).

I don't remember seeing a bench where anyone has separated memory overclock from core overclock, so I do reserve the right to be wrong. :D
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that is itself a fact that how those cards need that 384 bit bus and the bandwidth. what's the point of all that GCN architectural improvements if the 280X being 4 year old tech its still neck to neck and/or better in most cases?. this TPU review show the 280X being better in 10 of 14 games versus 380X.. that speak itself of how bus/bandwidth greatly benefit GCN.
 
Yes, but the margins of advantage are generally (I looked at 1920x1080 results, as that's where this guy belongs), which means the much, much larger available bandwidth ain't buying much. BF3&BF4 seem to tax this the most. On the flipside, Civ5 plays much much better on the 380x.

It's predominately limited by the chipset, not the bus. Outside of the memory compression and TrueAudio, is there really much differentiating the 380x from the 280x? Obviously the 384 bus vs the 256 bus. 4 year old chip or not, I don't think the actual processing engine has moved too terribly much.

Edit to add--the overclocking results given in that same article (on BF3, which is one of the major differentiators) doesn't see a gigantic boost from overclocking just the ram. Not complaining about it, though!
 
Dat apple money.....I tell ya thats why!

Honestly not shocked at all. I think they should of put 6GB of ram on it and 384 bit bus, at the price it is now would of been a seller.

Just my 0.02c
 
Araxie said:
that is itself a fact that how those cards need that 384 bit bus and the bandwidth. what's the point of all that GCN architectural improvements if the 280X being 4 year old tech its still neck to neck and/or better in most cases?. this TPU review show the 280X being better in 10 of 14 games versus 380X.. that speak itself of how bus/bandwidth greatly benefit GCN.
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There's more advantages than technical specs; availability, being able to purchase new, OEM pickup / sales, warranty status, and marketability to name a few. Perhaps they don't have the huge R+D budget of time allocated to rolling out a Q4 product when they're rolling out a new architecture next summer. They're just looking to fill the market gap by producing a, "New" product.
 
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