There's too much difference between DDR3 and GDDR5 VRAM?

[SANICADVENTURE2]

I bought a new notebook with an ATI mobility 5850 video card and I got dissapointed when I discovered that the card has DDR3 dedicated VRAM.

My desktop video card (the same ati 5850) has gddr5 and according to gpu-z the desktop card has 128GB/s of memory bandwidth, but the notebook card 12.8GB/s

The worst is when I see the integrated INTEL HD card even has more memory bandwidth (arround 14GB/s).

WTF IS THIS????? IS THIS TRUE????? THAT "AWESOME" ATI CARD IS PURE GARBAGE DUE TO A SHITTY VRAM????? Does affect too much the use of dedicated DDR3 VRAM instead GDDR5 VRAM?????

[Ny]

It's just a cheaper option for notebooks as DDR3 costs only a small fraction compared to GDDR5. As for the bandwidth the GDDR5 Graphics card will have a higher bandwidth due to the nature of GDDR5 having a higher bandwidth but lower latency than DDR3 RAM. The Intel HD is integrated into motherboard therefore the bandwidth can be built in easily.

[TESLA-X4]

Iirc GDDR3 delivers data twice per clock, GDDR5 does that four times per clock, which means that clock for clock, GDDR5 is twice as fast. But that's just half of the story. Due to GDDR5's higher transfer rate, manufacturers tend to pair them with smaller interfaces (since wider interfaces are more expensive to design and manufacture).

Basically:
GDDR3 @ 500 MHz on a 512 bit interface = GDDR5 @ 500 MHz on a 256 bit interface.
Why?
500 x 2 x 512 = 500 x 4 x 256

Some diagnostic applications will scale the reported memory bandwidth based on the currently active performance level of the graphics card, so check that your card is actually running at full speed and not staying in power save mode.

Also, kindly go easy on the punctuation.

Edit:
FFFFFFF lured into an old thread by Ny D:

[Ny]

Muhahaha, I should really clear out my unread post counts >_>