LOL_Wut_Axel
Diamond Member
- Mar 26, 2011
- 4,310
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I'm seriously hoping for a big IPC increase.
Core (45nm) has ~10% higher IPC than K10.5, Nehalem has ~10% higher IPC than Core, and Sandy Bridge has ~15% higher IPC than Nehalem. This is not counting HyperThreading (it's not part of the IPC equation), so add 20% for that in multi-threaded apps.
What you end up with is with the fact that Intel has ~35% higher IPC than AMD currently. AMD got a 30% performance boost in heavily multi-threaded apps from the Phenom II X6 in comparison to the X4, so in those it can either match or be slightly slower than the Core i5 2500. It's still 20% behind in them in comparison to the 2600 because of HyperThreading. They can only match the Core i5 in very multi-threaded apps, but at the expense of performance in anything that's not.
In the end, they need a 20% IPC boost in combination with high stock clock speeds to be able to not lose by a high amount in single-threaded apps while being able to have a considerable gain in multi-threaded apps, which is the main point of them making 8-core CPUs for consumers.
So, consider this scenario: AMD FX-6100 has a 20% gain over the Phenom II X6 1100T because of higher IPC. That means it can almost match the 2600 in very heavily threaded apps (3.4GHz vs 3.3GHz=2% advantage), but loses by ~17% in single-threaded ones. Then comes the two other ones: the FX-8150 and FX-8100. They both have two more cores than the 6100, which should give it an advantage of ~20% in multi-threaded apps. The FX-8100 has a clock speed of 2.8GHz, giving it a deficit of ~15% in comparison to the FX-6100's 3.3GHz. That means it should only be 5% faster in multi-threaded apps, or 3% faster than the i7 2600, but also 32% slower in single-threaded apps. But then they have the FX-8150, which not only benefits from the two added cores, but also higher stock clock speed. In comparison to the FX-6100, it should benefit from higher clock speeds in single-threaded apps by 8%, and in multi-threaded apps from both the higher clock speed and also by 20% from the additional cores. That means it would be ~9-10% slower than the i7 2600 in single-threaded apps and 28% faster in multi-threaded apps, both stock. If performance at the same clocks is the method of comparison, then it would obviously be ~15% slower in single-threaded apps. It would also mean that it would beat the Core i7 990X overall by a very slight margin (though it doesn't compete with that).
Of course, this is all taking into account Nehalem IPC. If it's 5% lower or higher, then obviously everything I said changes by that same percentage. Also, don't take everything I said as fact, since obviously IPC can be different, and there could be other factors to take into account. The main point that I was trying to bring up is that if it has Nehalem-level IPC it's pretty much the exact same CPU in terms of performance at the same clocks as Gulftown, which benefited by 20% because of HyperThreading, while Bulldozer would find that 20% benefit from the additional two cores.
Core (45nm) has ~10% higher IPC than K10.5, Nehalem has ~10% higher IPC than Core, and Sandy Bridge has ~15% higher IPC than Nehalem. This is not counting HyperThreading (it's not part of the IPC equation), so add 20% for that in multi-threaded apps.
What you end up with is with the fact that Intel has ~35% higher IPC than AMD currently. AMD got a 30% performance boost in heavily multi-threaded apps from the Phenom II X6 in comparison to the X4, so in those it can either match or be slightly slower than the Core i5 2500. It's still 20% behind in them in comparison to the 2600 because of HyperThreading. They can only match the Core i5 in very multi-threaded apps, but at the expense of performance in anything that's not.
In the end, they need a 20% IPC boost in combination with high stock clock speeds to be able to not lose by a high amount in single-threaded apps while being able to have a considerable gain in multi-threaded apps, which is the main point of them making 8-core CPUs for consumers.
So, consider this scenario: AMD FX-6100 has a 20% gain over the Phenom II X6 1100T because of higher IPC. That means it can almost match the 2600 in very heavily threaded apps (3.4GHz vs 3.3GHz=2% advantage), but loses by ~17% in single-threaded ones. Then comes the two other ones: the FX-8150 and FX-8100. They both have two more cores than the 6100, which should give it an advantage of ~20% in multi-threaded apps. The FX-8100 has a clock speed of 2.8GHz, giving it a deficit of ~15% in comparison to the FX-6100's 3.3GHz. That means it should only be 5% faster in multi-threaded apps, or 3% faster than the i7 2600, but also 32% slower in single-threaded apps. But then they have the FX-8150, which not only benefits from the two added cores, but also higher stock clock speed. In comparison to the FX-6100, it should benefit from higher clock speeds in single-threaded apps by 8%, and in multi-threaded apps from both the higher clock speed and also by 20% from the additional cores. That means it would be ~9-10% slower than the i7 2600 in single-threaded apps and 28% faster in multi-threaded apps, both stock. If performance at the same clocks is the method of comparison, then it would obviously be ~15% slower in single-threaded apps. It would also mean that it would beat the Core i7 990X overall by a very slight margin (though it doesn't compete with that).
Of course, this is all taking into account Nehalem IPC. If it's 5% lower or higher, then obviously everything I said changes by that same percentage. Also, don't take everything I said as fact, since obviously IPC can be different, and there could be other factors to take into account. The main point that I was trying to bring up is that if it has Nehalem-level IPC it's pretty much the exact same CPU in terms of performance at the same clocks as Gulftown, which benefited by 20% because of HyperThreading, while Bulldozer would find that 20% benefit from the additional two cores.
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