HD 4890 vs GTX 275 – Specs Leaked

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The thing is, the ddr5 doesnt matter if the 275 has the bigger bus.

GDDR5 is more than twice the speed of GDDR3 so to beat it the 275 would need more than double the bus length. It doesn't.

Really the GTX275 is Nvidia trying to steal ATI's fire form the launch of their card. Its a reaction card and really adds nothing to their line. The current GTX cards cover every aspect of that market segment. Instead of playing tricks they should work on trying to beat ATI in a price war or something more productive. the 275 is simply a 280 with the 260's memory interface.
 
GDDR5 is more than twice the speed of GDDR3 so to beat it the 275 would need more than double the bus length. It doesn't.

Really the GTX275 is Nvidia trying to steal ATI's fire form the launch of their card. Its a reaction card and really adds nothing to their line. The current GTX cards cover every aspect of that market segment. Instead of playing tricks they should work on trying to beat ATI in a price war or something more productive. the 275 is simply a 280 with the 260's memory interface.

Except that ddr5 is NOT more than double the speed. The 4870 runns at roughly 4ghz, the 285 runs at 2500+. So therefore, the bus speed more than makes up for the speed of the ddr5.

Also, why does everyone hate Nvidia for being having better marketting than ATI. Ati has done every single "trick" that nvidia has done, just at different times. I guess its just trendy to hate on nvidia right now.

ATI 975mhz x4= 3900 x (256bit bus / 8) = 124800mb
Nvidia 1161mhz x2= 2322 x (448bit bus / 8) = 130032mb
Thats only 1.6x as fast. Also, when overclocking memory, you gain more bandwidth out of a wider bus than you do out of faster memory.
 
so i guess the 4890 is a 55nm overclocked 4870 1GB? things look to be heating up soon.

The 4870 and 4850 were both 55nm already. Some sites have said that the rv790 die is actually bigger than rv770 but so far they haven't released what changes have been made.
 
Except that ddr5 is NOT more than double the speed. The 4870 runns at roughly 4ghz, the 285 runs at 2500+. So therefore, the bus speed more than makes up for the speed of the ddr5.

Also, why does everyone hate Nvidia for being having better marketting than ATI. Ati has done every single "trick" that nvidia has done, just at different times. I guess its just trendy to hate on nvidia right now.

ATI 975mhz x4= 3900 x (256bit bus / 8) = 124800mb
Nvidia 1161mhz x2= 2322 x (448bit bus / 8) = 130032mb
Thats only 1.6x as fast. Also, when overclocking memory, you gain more bandwidth out of a wider bus than you do out of faster memory.

GDDR5 (not DDR5) is not the same clock for clock as GDDR3.

GDDR4 SDRAM introduced DBI (Data Bus Inversion) and Multi-Preamble to reduce data transmission delay. Prefetch was increased from 4 to 8 bits. The maximum number of memory banks for GDDR4 has been increased to 8. To achieve the same bandwidth as GDDR3 SDRAM, the GDDR4 core runs at half the performance of a GDDR3 core of the same raw bandwidth. Core voltage was decreased to 1.5 V.

And

GDDR5 is the successor to GDDR4 and unlike its predecessors has two parallel DQ links which provide doubled I/O throughput when compared to GDDR4.

So yes for the same clock and data width GDDR5 is over twice as fast.

The 4870 has 115.2 GB/s of memory bandwidth. The GTX260 has 111.9GB/s.
 
obviously i meant gddr5, as ddr5 does not exist. And i did the math up there which just shows that the 275 does in fact keep up with and even beats the 4890. And again, no, it is NOT twice as fast. Gddr5 runs about 1.6x as fast as Gddr3.
 
HD 4890 looks better on paper. The GDDR5 should give it somewhat of an edge. The pricing looks fairly equal.

If you look at specs, you would notice that the difference between GTX 260 and GTX 275 is bigger than than the difference between HD4870 and HD4890

GTX 275 has %9.8 higher clock, %13 higher shader speed and %16 higher memory speed . Plus it have %11 more stream processors (240 vs 216).

HD4890 has %13.3 higher clock and 8.3% higher memory speed than HD4870. No increase in stream processors !!
 
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