onlysublime
New member
The Surface Pro 4 i5 comes with Intel HD Graphics 520 (GT2) and has 24 Execution Units (EUs) clocked at up to 1050 MHz (depending on the CPU model). Due to its lack of dedicated graphics memory or eDRAM cache, the HD 520 has to access the main memory (2x 64bit DDR3L-1600 / DDR4-2133).
The Surface Pro 4 i7 comes with Intel Iris Graphics 540 (GT3e) which has 64 MB of dedicated eDRAM memory. Furthermore, the so-called GT3e-version features 48 Execution Units (EUs) clocked at up to 1050 MHz (depending on the CPU model). Besides the eDRAM cache, the Iris 540 is able to access the main memory (2x 64bit DDR3L-1600 / DDR4-2133).
So theoretically, the Iris graphics is twice as fast as the graphics in the i5 because it has twice the number of execution units. You don't get true 100% difference between 540 and 520 because the 520 actually has faster texture fill rate. But shader performance is more important and the 540 has over 2X the shader performance.
But the main reason why 540 is not 2x faster is both systems are bottlenecked by the system RAM. The Iris has eDRAM which greatly helps. While eDRAM is faster than dedicated video RAM, it's limited by the fact that you only get 64 MB versus desktop graphics which have 1 GB-8 GB of dedicated video RAM for the midrange to high end cards respectively. While your data is in that 64 MB space, you'll get great framerates. But moving data from system RAM (slow) to eDRAM takes time and that results in a big drop in frame rate. So the goal is to keep all the data within that 64 MB. Which is the reason why you go with a lower resolution because lower resolution consumes less memory.
Now the difference between Core i5's 520 and the Core M3's 515 is closer than the difference between the i7's 540 and the i5's 520. The main difference is the memory controller where the 520 is 5 GB/sec faster than the 515.
But how is that in the real world? This is only a few published tests. And it's with immature drivers. Once Intel gets their act together and fixes the drivers, the i7 Iris graphics should shine even more.
GFXBench Windows OpenGL - 1080p Manhattan 3.1 Offscreen (Top Scores)
Iris™ Graphics 540 (15W Skylake-U GT3e): 63.5 FPS
HD Graphics 520 (15W Skylake-U GT2): 39.6 FPS
Iris™ Pro Graphics 5200 (47W Haswell-H GT3e): 61.2 FPS
HD Graphics 5000 (15W Haswell-U GT3): 36.7 FPS
Geforce GT940M: 52.3 FPS
Surface Book's Geforce dGPU: 61.1 FPS
540 vs 520:
Compubench:
Face Detection
28.8 mPixels/s
18.632 mPixels/s
TV-L1 Optical Flow
4.546 mPixels/s
2.731 mPixels/s
Ocean Surface Simulation
341.639 Frames/s
201.624 Frames/s
Particle Simulation - 64k
224.953 mInteraction/s
172.934 mInteraction/s
T-Rex
2.186 Frames/s
1.425 Frames/s
Video Composition
8.536 Frames/s
9.542 Frames/s
Bitcoin Mining
49.109 mHash/s
26.351 mHash/s
Significant gains between Iris 540 and HD 520.
The guy who started this thread hasn't answered any of the questions I asked. What temps are he getting? Lots of software out there to measure. What resolution is he running his game? How much SSD space does he have available?
That brings up another point. Bigger sized SSD work faster than smaller SSD because of how SSDs are designed. Check the specs between different sized drives and see how that bears out. Free space on an SSD is also important. The more you fill the SSD, the slower it gets. You don't want to touch a 128 GB SSD if you actually want great performance.
And Werewolf's observations for Surface Pro 3 don't apply to Surface Pro 4. The Surface Pro 3 was designed when they thought it would have the thermals of Broadwell. But Broadwell was extremely late and so they reused Haswell. When your cooling system is designed for the cooler running Broadwell and you suddenly have to have the hotter Haswell, you're going to experience throttling. Which is why the i7 SP3 was not much different than i5 SP3 during sustained loads.
Not only does SP4 have a better cooling system, it's 2 generations newer than Haswell. So comparing i5 to i7 (especially factoring in Iris) will make a much greater difference than during the SP3 days.
The Surface Pro 4 i7 comes with Intel Iris Graphics 540 (GT3e) which has 64 MB of dedicated eDRAM memory. Furthermore, the so-called GT3e-version features 48 Execution Units (EUs) clocked at up to 1050 MHz (depending on the CPU model). Besides the eDRAM cache, the Iris 540 is able to access the main memory (2x 64bit DDR3L-1600 / DDR4-2133).
So theoretically, the Iris graphics is twice as fast as the graphics in the i5 because it has twice the number of execution units. You don't get true 100% difference between 540 and 520 because the 520 actually has faster texture fill rate. But shader performance is more important and the 540 has over 2X the shader performance.
But the main reason why 540 is not 2x faster is both systems are bottlenecked by the system RAM. The Iris has eDRAM which greatly helps. While eDRAM is faster than dedicated video RAM, it's limited by the fact that you only get 64 MB versus desktop graphics which have 1 GB-8 GB of dedicated video RAM for the midrange to high end cards respectively. While your data is in that 64 MB space, you'll get great framerates. But moving data from system RAM (slow) to eDRAM takes time and that results in a big drop in frame rate. So the goal is to keep all the data within that 64 MB. Which is the reason why you go with a lower resolution because lower resolution consumes less memory.
Now the difference between Core i5's 520 and the Core M3's 515 is closer than the difference between the i7's 540 and the i5's 520. The main difference is the memory controller where the 520 is 5 GB/sec faster than the 515.
But how is that in the real world? This is only a few published tests. And it's with immature drivers. Once Intel gets their act together and fixes the drivers, the i7 Iris graphics should shine even more.
GFXBench Windows OpenGL - 1080p Manhattan 3.1 Offscreen (Top Scores)
Iris™ Graphics 540 (15W Skylake-U GT3e): 63.5 FPS
HD Graphics 520 (15W Skylake-U GT2): 39.6 FPS
Iris™ Pro Graphics 5200 (47W Haswell-H GT3e): 61.2 FPS
HD Graphics 5000 (15W Haswell-U GT3): 36.7 FPS
Geforce GT940M: 52.3 FPS
Surface Book's Geforce dGPU: 61.1 FPS
540 vs 520:
Compubench:
Face Detection
28.8 mPixels/s
18.632 mPixels/s
TV-L1 Optical Flow
4.546 mPixels/s
2.731 mPixels/s
Ocean Surface Simulation
341.639 Frames/s
201.624 Frames/s
Particle Simulation - 64k
224.953 mInteraction/s
172.934 mInteraction/s
T-Rex
2.186 Frames/s
1.425 Frames/s
Video Composition
8.536 Frames/s
9.542 Frames/s
Bitcoin Mining
49.109 mHash/s
26.351 mHash/s
Significant gains between Iris 540 and HD 520.
The guy who started this thread hasn't answered any of the questions I asked. What temps are he getting? Lots of software out there to measure. What resolution is he running his game? How much SSD space does he have available?
That brings up another point. Bigger sized SSD work faster than smaller SSD because of how SSDs are designed. Check the specs between different sized drives and see how that bears out. Free space on an SSD is also important. The more you fill the SSD, the slower it gets. You don't want to touch a 128 GB SSD if you actually want great performance.
And Werewolf's observations for Surface Pro 3 don't apply to Surface Pro 4. The Surface Pro 3 was designed when they thought it would have the thermals of Broadwell. But Broadwell was extremely late and so they reused Haswell. When your cooling system is designed for the cooler running Broadwell and you suddenly have to have the hotter Haswell, you're going to experience throttling. Which is why the i7 SP3 was not much different than i5 SP3 during sustained loads.
Not only does SP4 have a better cooling system, it's 2 generations newer than Haswell. So comparing i5 to i7 (especially factoring in Iris) will make a much greater difference than during the SP3 days.