A friend of mine is going to be upgrading his CPU very soon, and I'm unsure whether to tell him to wait for Haswell or not. I fully understand that the main upgrade with Haswell is a monstrous onboard GPU upgrade (almost twice that of Ivy Bridge), but I read an article that also stated "Haswell [is] expected to be around 10-15% faster than Ivy Bridge." I will note that the quote came with unsupported evidence. Also note that he uses discrete graphics, and would get no benefit from the souped-up onboard GPU.
I should clarify that I'm specifically looking at the comparison of the i5-3570K to the i5-4570K. They both have the same technical specs: 3.4/3.8, unlocked, 7MB L2 + L3 cache.
One thing that is different is that according to cpu-world.com the 3570K features F16C instructions("which are not widely used"), while the 4670K features AVX2 instructions("which are also not widely used"). Also, the 4670 has 7W more TDP.
So in reading just the raw specs I don't see how the aforementioned article claimed that Haswell is expected to be 10-15% faster than Ivy Bridge, and I'm unsure whether to tell my friend to wait or not. If Haswell truly is 10-15% faster then I would want him to get one of the new chips since he rarely upgrades his computer parts. However, if it is not then I'd just tell him to scoop up an Ivy Bridge CPU.
The thing is, if your friend already has a 1155 motherboard, and doesn't want to change his mobo, then he can't even get the new Haswell chips, since they use 1150 sockets (which aren't compatible with 1155 unfortunately).
That being said, even if he doesn't want to make the switch to a 1150 mobo, one could expect the Ivy chips to slightly drop in pricing when Haswell releases.
So with that in mind, I would wait regardless... I mean it's releasing at the end of the month so if your friend can hold on just a little bit longer, he can either:
-Get a new mobo + Haswell and get the top of the line chip
-Get a great gaming chip (3570k) at a slightly reduced price
I'm not sure of his exact specs, but just note that his motherboard will be upgraded when he upgrades his CPU (that was part of his original plan). His GPU is a 560ti, perhaps to be upgraded at some point in the future. His memory is just some basic 1333 DDR3, nothing fancy. He has an HDD and will be purchasing an additional SSD for games.
In the grand scheme they probably won't notice the difference. Do they want the machine now with no future upgrad-ability, or wait and possibly upgrade the CPU during the PC's lifetime. Answer that and you'll have the answer as to which CPU to use.
From what I've read, the average user will not notice any CPU speed improvement until it reaches 10% or more. I've also read that Haswell will only be 7-12% more improvement on the CPU side.
"So in reading just the raw specs I don't see how the aforementioned article claimed that Haswell is expected to be 10-15% faster than Ivy Bridge"
Haswell has a higher IPC (instructions per clock), that's how it gets more done at the same clock/specs as Ivy Bridge. It gets more work done per clock cycle, so at the same clock speed it will do more.
Ah, that's the hard-fact I was missing in my understanding of Haswell's speed improvement. I should know better, having just taken a class on computer architecture. Thanks everyone for your input, I'm gonna close this off. I think I am just going to have him go for the upgrade to Haswell since he's getting a new mobo anyway.