More cores or Hyperthreading for next gen/editing

Hyperthreading is a neat little technology that allows a single physical processor core to work on two logically isolated workloads at the same time (a single physical processor core is exposed as two logical processors). The core resources are balanced dynamically between the two workloads.

If one of the workloads is an idle thread, then the majority of the core's execution resources will be dedicated to the primary workload, effectively turning it into a powerful single core processor. This is why most people claim that "modern games don't take advantage of Hyperthreading", there aren't enough concurrent workloads in them to spill over.

If the two workloads are balanced, then the core's resources are spread between them almost evenly. At this point, the processor does behave as if it had twice as many physical cores, with each one somewhat less performant than it would be were Hyperthreading disabled.

example,

Workload A utilizes 50% of a cores resources and executes in 1 second. Workload B utilizes 25% of a core's resources and executes in 0.5 seconds. Workloads A and B are disjoint, sharing no common execution resources (impossible in reality, but good for this example).

If Hyperthreading is disabled, the microprocessor must execute workloads A and B sequentially, consuming a total of 1.5 seconds of time between them.

If Hyperthreading is enabled, the microprocessor can execute workloads A and B concurrently, provided that it has the resources to do so. In this example, there's plenty of compute power left over so A and B can run at the same time. B will finish first after 0.5 seconds, followed by A 0.5 seconds later (total of 1 second run time).

If the workload of B is increased to 75% for 1.5 seconds, then the combined workloads exceed 100% of the core's resources.

If Hyperthreading is disabled, the two workloads still take 2.5 seconds.

If Hyperthreading is enabled, then the processor has to balance between A and B. Lets assume a perfect 50/50 split,

Workload A gets 50% of the core's resources and completes within 1.0 seconds as before. Workload B gets 50% of the core's resources but requires 75% to execute within 1.5 seconds. For the first second, it is only able to use two thirds of the resources that it needed to complete the workload within the non-Hyperthreaded completion time. Lets do some math,

0.75 * 1.5 = 1.125

1.125 - 0.5 * 1.0 = 0.625

0.625 / 0.75 = 0.833 seconds remaining

So rather than taking 1.5 seconds to execute, it takes 1.833 seconds to execute. This is longer than it would take had it full access to the core's execution resources, but it executes concurrently with workload A which still reduces the combined execution time from 2.5 seconds to 1.833 seconds. Not a bad increase!

/Hyperthreading tutorial

pinhedd gave a good explaination of hyperthreading. However keep in mind that the overall increase in performance is closer to 20% but still a sizable increase. Hyperthreading may come into play in next gen games, however I wouldn't worry too much about. Even an i5 3570k will be able to handle next gen games quite well I would think. Honestly hyperthreading isn't that big of an increase so I doubt it will come into play for gaming. The i7 would handle the games about the same as an i5, maybe a little better if hyperthreading plays nice with games (there are some games out now that perform worse with hyperthreading enabled).

That being said, I don't think that next gen games are going to be what i'd call heavily multi-threaded. I could see 4 heavily loaded cores on an 8350, with the rest being lightly loaded (say 20-35% usage tops). They will mostly likely be multi-threaded, but not enough to really say which architecture will be the "winner".

Honestly you'd probably be fine with either an i5, i7 or 8350. It all comes down to what you do outside of games that makes the difference between processors. If you do video/photo editing, CAD, video encoding/ripping, etc... then an 8350 or (if you can afford it) an i7 would be a good choice. If you don't use a lot of heavily threaded applications then an i5 or 8320/50 or even a 6300/50 would work well. If you can afford intel with a good graphics card (say a GTX 760 or better) then I'd say you'd be just fine with that.

Future proofing is a term that gets thrown around a lot, I wouldn't say an i7 is any more future proof than an i5 for gaming for the next 3-5 years. Hyperthreading isn't that big of an increase in performance and it might not play nice with multi threaded games (since as pinhedd pointed out, it could cause a process to take longer to finish which might cause stuttering. this is purely speculation though). Besides, the i5 has enough power to muscle its way through it.

While it's true that games will not use hyperthreading themselves because a game may be designed to use 3 or 4 cores it's what else that wants to run in the background that could demand resources. How many people will have a second or even a third monitor that may not be used for the game but rather having a web page open or a movie running or several monitoring apps open to what temps and FPS.
This is where hyperthreading comes into play and becomes useful.

Game developers won't be making games that use 8 cores because then they will be restricting their games to be sold to the few that have 8 cores. For the forseeable future a quad core will be the mainstream target CPU of game developers. Even now if you look at the minimum requirements it's still listing a dual core CPU because there are a lot of people that have that. Eventually as they upgrade and quad cores become cheaper then everyone will have one and the games will start to move towards more cores as 8 or more cores become mainstream.