That is my point ! Same cache. The G3220 is almost an i3...
http://www.cpu-world.com/Compare/290/Intel_Core_i3_i3-3220_vs_Intel_Pentium_Dual-Core_G3220.html
(although they are comparing 3.3GHz Ivy-i3 vs 3.0GHz Haswell G3220)
I wasn't looking at the specific part you mentioned, but that comparison (and most of them from cpu-world, unfortunately) isn't very good.
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Most desktop Haswell Pentiums only have 3MB of L3, whereas most Core i3s have 4MB. Haswell was "designed" for larger caches (the desktop Core i5 and i7s have 6-8MB), so that cut can be substantial for an already cache-limited CPU at the low end.
* All mobile Haswell Pentiums only have 2MB of L3, wheras all Core i3s have 3MB.
* As connersw pointed out, none of the Pentiums have HyperThreading. With the larger front-end since Nehalem, HyperThreading has actually become very useful in most desktop use-cases, and almost never hurts you (unlike the prior implementation on the P4)
* Most of the Pentium and Celeron CPUs have no support for x86 extensions such as AVX, AVX2, FMA3 and AES-NI. All of the Core i3s do (I couldn't find specifics saying NONE of the Pentiums do, so you'd have to look). AVX and AVX2 in particular can impart impressive performance gains in the right workload (the fused multiply-add can be massive). The FMA3 SMID extensions are also massive (one of the nice things about Bay Trail over prior Atoms is the vastly improved SMID engine). And, of course, the AES hardware block is huge if you'll ever encrypt volumes on the system with AES (I'd always use AES combined with another cypher, so I'd see less benefit here).
There are a number of things you lose with the Pentiums, besides raw clockspeed and cache. It all depends on the workload, but in my estimation, it often isn't worth the price difference. If it'll work for your workload, though, and you find a particularly good deal (or all the i3s are selling at or near list), well... Then it might be worth it. I was just making a general statement that the i3s are much less "gimped".
You can no longer compare CPUs based solely on clock speed, or even cache for that matter. Atom, Pentium, and Core processors are all different architectures targeted towards different uses. Celeron is a bit of an outlier. It is basically just low bin split chips, that we used to make key chains out of, that we started selling to customers at a deep discount in the late 90s to combat AMD's aggressive price war. They can be based on Pentium or Core architecture.
I agree with everything you said in principle. However, right now (so long as you don't buy an old part) the Pentiums and Celerons Intel is shipping ARE Haswell, so it is the
same architecture. They're certainly gimped ones and ones that bin out low. Intel's process is so good though, that I bet they produce far more high-binned parts than they can sell at high-end prices (hence all the artificial segmentation we see now).
That said, you're right that Bay Trail is a very different architecture, and that clockspeed isn't everything.
Like I said, I agree generally. But Haswell is Haswell, inside.