Bcm4709 vs 7621a

Hello all! Have a couple (11-15) routers to choose, most of them based on BCM4709 or MTK7621A,
wich CPU is more powerfull (for qos for example), and what is better supported for OWRT?

The BCM should be "faster", but it'll have crippled wifi (if any, at all), compared to the MTs, see for instance https://openwrt.org/toh/asus/rt-ac87u, even though some wiki info might be outdated.

Something to keep in mind that while the Broadcom CPU is faster per core, the MT7621 is a quad core while the BCM4709 is a dual core. This becomes important to throughput as it impacts how IRQs can be distributed. You can have Ethernet IRQs handled on one core, Wi-Fi on another, and still have two cores to handle user-space. I have done a lot of benchmarking, and my Netgear R6700v2 (MT7621) significantly outperforms my R6700v1's (BCM4709A) in all real-world performance tests.

Broadcom's Wi-Fi drivers (which, as noted by @frollic, are not supported in OpenWRT) are notorious CPU hogs anyway. As an aside, I have long suspected that Broadcom chipsets are to Wi-Fi what the old winmodems were to modems. For example, I have noted that high CPU usage on a Broadcom device will actually cause rapid degredation and fluctuation of its negotiated PHY data rates with clients. This is why I suspect they have offloaded certain elements normally in silicon onto the driver. This would also explain why Broadcom very jealously guards its drivers and won't let anyone see them except under strict NDA.

In short, I think you'll be much happier with MT7621. In all ways that matter, it is simply superior to the BCM4709.

why you writing 7621 is a quad core? it is dual core, i took bcm4709 based router anyway

Sorry, correct. It has two physical execution units, with two scheduler units per core. Two physical cores, four virtual.

Let us know your experience with it.

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