I wanna ask if is better to have 8/128 or 16/64?
Im looking for Archer C6 v2 or RT-AC51U
(Im not gonna use lan ports).
It is better to have 16/128.
Between those two I'd definitely choose the C6. If you tried to install enough packages to need 16 flash, you'd find that 64 RAM is not enough to run them.
I know what is better but i have only these two options 16/64 or 8/128.
You can make do with 8 MiB flash if needed. Extra RAM is handier than extra flash in this case I'd say.
The only thing that i want is something to reduce bufferbloat, so i will install anything SQM related.
First consideration in any router selection is ISP speed. Neither one of those have a lot of CPU power (and notably the AC58U is about 25% slower). I would say ISP speed should be less than 50 Mb.
My internet speed atm is 50/5.
Maybe i will take the Archer C6.
Lack of FLASH can be compensated with an external USB drive, lack of RAM cannot be compensated.
To a certain extend you can extend RAM by using zram for swapping, but only if the swapped memory has a good compression ratio.
The Archer C6 should be by far a better choice, not just because of the better RAM size, but also because of the SOC- and wireless side. mt7620 (as in the RT-AC51U) is an older, slower 1*560 MHz SOC, coupled with old rt2x00 wireless chipsets - the archer c6 (v3) is the much newer/ faster mt7621 SOC running at 2*880 MHz, combined with much better supported mt76 wireless chipsets (yes, mt7603e and mt7613 aren't quite perfect, but still better supported than the r2x00 based SOC internal 2.4 GHz wireless of the RT-AC51U).
I didnt know that but Archer C6 V2 dont have a usb port.
How can i use zram?
With a usb i can extend my flash or my ram? I confused.
I also see V2 not V3 and the alternatibe is RT-AC51U.
Oh and i also see that archer c6 v2 does not have good performance at 5ghz after flashing openwrt.
The archer c6 v2 would be ath79 based, in terms of CPU power somewhere inbetween mt7620 and mt7621 - but still much better (ath9k+ath10k) wireless than the RT-AC51U - so regardless of v2 or v3, the archer c6 would be the better choice.
I just read that zram is only for increase ram not flash.
But as i said archer dont have usb port, but 128mb its ok.
The "problem" is 8MB flash.
Almost everyone told me archer c6 v2 > RT-AC51U.
'Problem' is a relative term here. 4 MiB is dead in the water, but I still have some of those devices that I use (repeater, or a testing device). You cannot run a full modern OpenWrt on it - but you can strip some. Lots of people strip IPv6 (not the best idea), but also PPP, which needs a lot of space.
You won't immediately run into problems if you're using 8 MiB flash. But with flash sizes being powers of 2, the next cut-off will be 8 MiB at some point. Hence the present recommendation to buy 16/128: to do some foolproofing. Then again, you might find yourself buying an AX device once they become affordable, and you might never get into trouble with 8 MiB flash. I sure have quite a few of those myself still.
Like said before: it's easier to work around limited flash. You can strip packages to some extent. You can't tell programs to use less memory (RAM) than they actually need.
The third option is Tenda AC10U with 16/128, cpu RTL8197FS 1GHz and usb.
But no support for openwrt.
(All of them i can find in the same price here in Greece ~40€)
You can forget about OpenWrt for that device straight away, it's not going to happen.
C6 is better than RT-AC51, if 8MB flash is not enough for you, its can be upgrade easily than upgrade ddr2 RAM.