Using GDDR5 or DDR4? It is a big boost DDR3 even using triple or quad-channel.

You can expect bandwidth over 80GB/s with 128bits easy.

AMD is right... DDR3 is already old and now it is starting to become expensive.

GDDR5 (and DDR4 after launch) will be even more cheaper when the mass production for APU, console and GPUs started.

And remember the "latency" is more related to the memory controller than the memory itself... the memory controller in GPU that have a high latency and not the GDDR5.

You can achieve over 80GB/s with DDR3 already, you just need Quad-Channel DDR3 2600mhz or higher Ram to achieve it. :P

DDR4 won't be that much better than high-end DDR3 when it launches (It's supposedly launching at 2400mhz speeds), especially compared to those Samsung modules that can clock to 3ghz.
Over time however, it should have much bigger legs, much like DDR3 compared with DDR2.
The big benefit that DDR4 will bring initially will be power consumption, which is a massive boon for mobile devices.

It's both that effects latency.
http://en.wikipedia.org/wiki/CAS_latency

However, Memory Manufacturers set the clock rates, latencies and such for the memory in the Rams SPD (EEPROM), the computer's memory controller should recognise it and apply it.
Usually though they follow the JEDEC standard.
If the motherboard/memory controller doesn't recognise the settings, it will default to a standard 1333mhz speed and accompanying timings.

http://en.wikipedia.org/wiki/Serial_presence_detect
http://en.wikipedia.org/wiki/EEPROM

Edit: Personally I can't wait for DDR4 and Haswell-E, Haswell-E should bring with it a good 20-30% performance improvement per clock over Sandy-Bridge-E  and throw another 2 cores at the performance problem, which to me makes it worth upgrading from my 3930K finally.
But, it ain't going to be cheap. :( #Firstworldproblems

uh, like I said, 256bit would actually make a big difference since that bandwidth is still terrible on 128bit lol. ^_^;

Bright Side of News can be abbreviated to BS News for a reason

This is completely made up. AMD don't have the cash or the reason to do DDR4 in 2013. There won't even be any retail units of it. Intel isn't doing it until 2014 and then only for the very high end.

GDDR5 is even more far-fetched. AMD don't have the market precense to dictate such a switch.

I will bet heavily against either of these things. I'll buy you a Steam game.

ethomaz, this is nothing to do with tech and everything to do with cash.

Would DDR4/GDDR5 be faster? Yes. Can they be done, by AMD, in 2013? No!

1. AMD do not have a 20nm process available to them. Not in 2014, not ever.

2. Excavator is most likely cancelled.

AMD Supporting GDDR5 wouldn't be a replacement for DDR3 or DDR4, it's purpose would be purely for Graphics.
However, if we are to go by what AMD has done in the past, the GDDR5 memory will probably be used as Side-port memory, AMD did a similar thing with it's Xpress, Radeon 2000, 3000 and 4000 series of IGP's where it bundled dedicated DDR3/DDR2 memory dedicated to the graphics.

However, they lacked any decent amounts of bandwidth so the performance benefit was minimal at best, the main improvement though came from lower  latency as Physics comes into play. (Closer the memory is to a processor, the lower the latency.)

The other side of the coin though is cost, GDDR5 isn't *Super cheap* yet (Otherwise low-end GPU's would all have it!), Kaveri and AMD's other  APU's are cost sensitive, so they will probably leave it up to the motherboard manufacturers (Which would take on the cost burden) to decide whether they want the GDDR5 or not.

I could be completely wrong though, but it's my take on it. - But we will see once Kaveri launches.

That's definitely possible, but it's not the omg unified memory.

I know, but do you *need* unified GDDR5 memory on low-end hardware such as that? The performance benefits would be minimal at best and the costs would be high.