HowTo: http://blog.ispsupplies.com/mikrotik-wireless-capsman-howto/

Manual: http://wiki.mikrotik.com/wiki/Manual:CAPsMAN

This guy suggested upgrading to V6 for better wireless throughput, then:

/interface wireless
set 0 band=2ghz-b/g/n channel-width=20/40mhz-ht-above country=******* disabled=\
    no disconnect-timeout=5s distance=indoors frequency-mode=regulatory-domain \
    ht-amsdu-limit=0 ht-amsdu-threshold=0 ht-rxchains=0,1 ht-txchains=0,1 \
    l2mtu=2290 max-station-count=12 mode=ap-bridge preamble-mode=short \
    security-profile=WPA2 wireless-protocol=802.11

Comments:

For some reason following settings improve throughput:

enable-nstreme=yes enable-polling=yes
hw-protection-mode=cts-to-self hw-protection-threshold=2347 hw-retries=4

I don't know why nStream should be enabled, but it was performed better with it than without it. And most important was:

ht-amsdu-limit=256 ht-amsdu-threshold=256

Decreacing AMSDU from 8192 increases throughput! I read opposite of this on many posts, but try it and you will see.

/interface wireless
set 0 adaptive-noise-immunity=none allow-sharedkey=no antenna-gain=3 antenna-mode=ant-a area="" \
    arp=enabled band=2ghz-b/g/n basic-rates-a/g=6Mbps basic-rates-b=1Mbps bridge-mode=enabled \
    channel-width=20/40mhz-ht-above compression=no country=RealCountry default-ap-tx-limit=0 \
    default-authentication=yes default-client-tx-limit=0 default-forwarding=yes dfs-mode=none \
    disable-running-check=no disabled=no disconnect-timeout=3s distance=indoors frame-lifetime=0 \
    frequency=2452 frequency-mode=regulatory-domain frequency-offset=0 hide-ssid=no \
    ht-ampdu-priorities=0 ht-amsdu-limit=256 ht-amsdu-threshold=256 \
    ht-basic-mcs=mcs-4,mcs-5,mcs-6,mcs-7 ht-guard-interval=any ht-rxchains=0,1 \
    ht-supported-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7,mcs-8,mcs-9,mcs-10,mcs-11,\
    mcs-12,mcs-13,mcs-14,mcs-15,mcs-16,mcs-17,mcs-18,mcs-19,mcs-20,mcs-21,mcs-22,mcs-23 \
    ht-txchains=0,1 hw-fragmentation-threshold=disabled hw-protection-mode=cts-to-self \
    hw-protection-threshold=2347 hw-retries=4 l2mtu=2290 mac-address=00:0C:42:F7:B6:E1 \
    max-station-count=7 mode=ap-bridge mtu=1500 name=wlan1 noise-floor-threshold=default \
    nv2-cell-radius=30 nv2-noise-floor-offset=default nv2-preshared-key="" nv2-qos=default \
    nv2-queue-count=2 nv2-security=disabled on-fail-retry-time=100ms periodic-calibration=default \
    periodic-calibration-interval=60 preamble-mode=short proprietary-extensions=post-2.9.25 \
    radio-name=000C42F7B6E1 rate-selection=advanced rate-set=default scan-list=default \
    security-profile=WPA2 ssid=MySID station-bridge-clone-mac=00:00:00:00:00:00 \
    supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps \
    supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps tdma-period-size=2 tx-power-mode=default \
    update-stats-interval=10s wds-cost-range=50-150 wds-default-bridge=none wds-default-cost=100 \
    wds-ignore-ssid=no wds-mode=disabled wireless-protocol=802.11 wmm-support=disabled
/interface wireless manual-tx-power-table
set wlan1 manual-tx-powers="1Mbps:5,2Mbps:10,5.5Mbps:10,11Mbps:10,6Mbps:17,9Mbps:10,\
     12Mbps:10,18Mbps:10,24Mbps:10,36Mbps:10,48Mbps:10,54Mbps:10,HT20-0:17,HT20-1:17,\
     HT20-2:17,HT20-3:17,\HT20-4:17,HT20-5:17,HT20-6:17,HT20-7:17,HT40-0:10,\
     HT40-1:10,HT40-2:10,HT40-3:10,HT40-4:26,HT40-5:25,HT40-6:24,HT40-7:20"
/interface wireless nstreme
set wlan1 disable-csma=no enable-nstreme=yes enable-polling=yes framer-limit=3200 \
     framer-policy=best-fit
/interface wireless align