They are hard to compare, especially with the rather limited feedback received for mt7622b in 1 GBit/s WAN situations (with/ without SQM) so far.
- mt7622b
- is ARMv8 (64 bit)
- cortex A53 (in-order superscalar execution pipeline)
- running at 2*1.35 GHz
- 2.4 GHz: 4x4:4 802.11n
- 5 GHz: 4x4:4 802.11ax (external, often mt7915e)
- ipq8064
- is ARMv7 (32 bit)
- KRAIT300 ~= cortex A15 (out-of-order superscalar execution pipeline)
- running at 2*1.4 GHz
- NSS/ NPU cores: 2*730 MHz
- 2.4 GHz: 4x4:4 802.11n (external, often QCA9980)
- 5 GHz: 4x4:4 802.11ac (external, often QCA9980, rarely Quantenna Topaz)
- ipq8065
- is ARMv7 (32 bit)
- KRAIT300 ~= cortex A15 (out-of-order superscalar execution pipeline) running at 2*1.7 GHz
- NSS/ NPU cores: 2*800 MHz
- 2.4 GHz: 4x4:4 802.11n (external, often QCA9984)
- 5 GHz: 4x4:4 802.11ac/ wave2 (external, often QCA9984)
- ipq8071
- is ARMv8 (64 bit)
- cortex A53 (in-order superscalar execution pipeline) running at 4*1.0 GHz
(factory-overclocked to 4*1.4 GHz in case of the Xiaomi AX3600)- NSS/ NPU cores: 2*1 GHz
- 2.4 GHz: 4x4:4 802.11n (external, often QCN5024)
- 5 GHz: 4x4:4 802.11ax (external, often QCN5054)
- ipq8074
- is ARMv8 (64 bit)
- cortex A53 (in-order superscalar execution pipeline)
- running at 4*2.2 GHz
- NSS/ NPU cores: 2*1.5 GHz
- 2.4 GHz: 4x4:4 802.11n (external, often QCN5024)
- 5 GHz: 2*4x4:4 802.11ax (external, often 2*QCN5054, virtually making this 8x8)
mt7622b seems to share very well optimized ethernet drivers with its (ra)mips based predecessors (e.g mt7621a), but is limited to 1 GBit/s ports due to its included switch hardware. In stock OEM firmware, The various ipq80xx systems rely on a proprietary NSS firmware, offloading parts of the networking to an ubicom32 derived little-endian NSS/ NPU core (well, two of them in all cases) and are designed to support up to 10 GBit/s ethernet (or 2.5GBASE-T/ 5GBASE-T) that way (you will rarely find those in practice on ipq806x devices, but they're common for ipq8074).
The Belkin rt3200/ Linksys E8450 should beat ipq806x in practice, but would lose against ipq8074 (ipq8071 might be a fairer head-to-hear competition) - both in terms of routing- and wireless performance. But while the Belkin rt3200/ Linksys E8450 is supported right now, ipq807x is not (yet).
But ipq806x is battle-tested by now, while mt7622b+mt7915e is still very new (and still being improved, with some fluctuations) - and ipq807x isn't supported yet at all. So fair comparisons remain hard for the 802.11ax chipsets, based on not enough data points or none at all in case of ipq807x. What is clear, is ipq806x maxing out somewhere between 400-650 MBit/s WAN speed (without sqm, with sqm just under 200 MBit/s), mt7622b seems to beat that - I have not heard enough feedback about the wireless performance/ stability (but no complaints either, everyone seems to have been rather pleased so far).