EastCoasthandle
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System Name | MY PC |
---|---|
Processor | E8400 @ 3.80Ghz > Q9650 3.60Ghz |
Motherboard | Maximus Formula |
Cooling | D5, 7/16" ID Tubing, Maze4 with Fuzion CPU WB |
Memory | XMS 8500C5D @ 1066MHz |
Video Card(s) | HD 2900 XT 858/900 to 4870 to 5870 (Keep Vreg area clean) |
Storage | 2 |
Display(s) | 24" |
Case | P180 |
Audio Device(s) | X-fi Plantinum |
Power Supply | Silencer 750 |
Software | XP Pro SP3 to Windows 7 |
Benchmark Scores | This varies from one driver to another. |
This thread was created to show the differences between the 4870 and 4890 based on the information I've read about. Since we know this isn't a 4870 that was simply overclocked there should be a better understanding of what is different between the 2.
What's different about the 4890's GPU?
So far, what I found out is that the GPU has a de-coupling ring around it's edge. This de-coupling ring adds 3million more transistors making the total transistor count 959 million (up from 956 million). From the video interview the RV790 is a new ASIC. So is it a new chip? Physically, yes it is based on the improvements made but there is no logic design changes.
The above pic should provide you with some ideas of what was changed.
What's different about the video card itself?
Below is a pic showing both the 4870 and 4890. You can clearly see that there is some differences between the 2.
4870 Heat Sink Design
4890 Heat Sink Design
Backside of the 4870
Backside of the 4890
4870 VRMs 3+2. To the right is the controller.
4890 2 VRMs 5+2. To the right are 2 two Volterra VT1165MF controllers.
4870
4890 Volterra VT1165 controllers
4870 2 phase memory power
4890 CSP VT242WF
Overall IMO, the power design of the 4890 appears to be better then the 4870. Only time will tell how well performance gets as drivers mature.
Please note that this post maybe edited if more information becomes available.
What's different about the 4890's GPU?
So far, what I found out is that the GPU has a de-coupling ring around it's edge. This de-coupling ring adds 3million more transistors making the total transistor count 959 million (up from 956 million). From the video interview the RV790 is a new ASIC. So is it a new chip? Physically, yes it is based on the improvements made but there is no logic design changes.
The above pic should provide you with some ideas of what was changed.
What's different about the video card itself?
Below is a pic showing both the 4870 and 4890. You can clearly see that there is some differences between the 2.
4870 Heat Sink Design
4890 Heat Sink Design
Backside of the 4870
Backside of the 4890
4870 VRMs 3+2. To the right is the controller.
4890 2 VRMs 5+2. To the right are 2 two Volterra VT1165MF controllers.
sourceTwo parallel SMD inductors are used for 5-phase GPU power supply: 3-phase CPLA-3-50 and 2-phase Pulse PA1312NL. Besides, the MOSFET power chips are of different models. Four of them are VT1165SF which cost $3.5 each, and the remaining one is VT1195SF. They all feature Chip Scale Package, built-in MOSFET and driver chip. VT1195SF is capable of delivering maximum current of 40A, and VT1165SF can deliver Max. 30A current.
That is to say, Radeon HD 4890 can deliver Max. 160A current to GPU, compared with Max. 120A on HD 4870, which lays the groundwork for high clocks and great overclocking potential for Radeon HD 4890.
4870
4890 Volterra VT1165 controllers
sourceRadeon HD 4890 has employed two Volterra VT1165MF controllers just like Radeon HD 2900XT. We believe both of the two controllers on HD 4890 are prepared for GPU power supply, as the inductances used in 5-phase power circuit are not exactly the same, and VT242WF chips for memory power supply already has function of controlling IC. But the case is different when it comes to Radeon HD 2900XT: One of the two Volterra VT1165MF controller serves GPU power supply, and the other one serves memory power supply.
Theoretically, one VT1165MF is capable of managing up to 6-phase power supply. One of the two PWM chips is possibly designed to control 3-phase circuit, and the other controls 2-phase so as to enhance the GPU power supply. Only one single VT1165MF controller costs about $3, which increases the cost of the whole card.
4870 2 phase memory power
4890 CSP VT242WF
sourceRadeon HD 4890 employs two CSP VT242WF chips (also from Volterra) for the 2-phase memory power supply to deliver more than 20A current, much more than the maximum current required by memory (about 12A). VT242WF has intergrated MOSFET and driver IC as well as control IC, so it costs $5, more expensive than VT1000 Series. Besides, Pulse ceramic SMD inductor is also adopted which provides better performance.
Radeon HD 4890 features multi-layer ceramic capacitors which are usually seen at the rear side of Intel’s CPUs. They’re capable of delivering steady performance and heat-resistant ability. Three Japanese solid capacitors can be found on the card as well.
Overall IMO, the power design of the 4890 appears to be better then the 4870. Only time will tell how well performance gets as drivers mature.
Please note that this post maybe edited if more information becomes available.
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