SQM Performance issues with TP-Link C2600

Hi.

I upgraded my Internet connection up to 250/20 Mb/s. I needed a more powerful router to handle it with SQM. The Netgear R7800 is quite expensive and I could get TP-Link C2600 40% cheaper then the competitors. So I bought it.

I configured it and I'm not very happy with SQM performance. I can get something around 160-180 Mb/s with SQM. That's not quite what I expected. The CPU is not the issue. There's plenty of power left.

I also tried the yesterday snapshot with the same config and the performance was terrible. Compered to the stable it's a disaster. The whole console was lagging as hell. I don't know what's the issue. I heard that Netgear R7800 (same platform) has issues with SQM. Can someone tell me more about it?

Thanks.

My SQM config:

config queue 'eth0'
	option enabled '1'
	option interface 'eth0'
	option download '237500'
	option upload '19000'
	option debug_logging '0'
	option verbosity '5'
	option qdisc 'cake'
	option script 'layer_cake.qos'
	option qdisc_advanced '1'
	option squash_dscp '1'
	option squash_ingress '1'
	option ingress_ecn 'ECN'
	option egress_ecn 'NOECN'
	option qdisc_really_really_advanced '1'
	option iqdisc_opts 'nat dual-dsthost diffserv4 rtt 300ms mpu 64'
	option eqdisc_opts 'nat dual-srchost diffserv4 rtt 300ms mpu 64'
	option linklayer 'ethernet'
	option overhead '18'
	option linklayer_advanced '1'
	option tcMTU '2047'
	option tcTSIZE '128'
	option tcMPU '64'
	option linklayer_adaptation_mechanism 'cake'