It may have a capacity of 75Mbps / 100Mbps / 200Mbps, because its bandwidth is 10MHz. The capacity depends on the technology available between phones and the tower.
Normally, this frequency is used for MTN's 2G, not 4G. Yet, the frequency was used for 4G at least once and in at least one area. A partial refarm.
It can be seen that Band 3 4G is in use with the *#0011# service menu on a Samsung phone.
Band 3 can also be added for carrier aggregation. In the screenshot, Band 3 and Band 20 are used together. Unfortunately, other metrics in the screenshot don't look good, but please do not guess that it's a problem with how the network is set up.
Other towers signal the availability of 4G Band 3. The phone's ability to reselect is available after 5 seconds of sending or receiving no data, handovers (network-assisted 'reselections') are performed otherwise.
sib3
cellReselectionInfoCommon
q-Hyst: dB4 (4)
cellReselectionServingFreqInfo
s-NonIntraSearch: 20dB (10)
threshServingLow: 4dB (2)
cellReselectionPriority: 7
intraFreqCellReselectionInfo
q-RxLevMin: -118dBm (-59)
s-IntraSearch: 62dB (31)
allowedMeasBandwidth: mbw100 (5)
.... ..1. presenceAntennaPort1: True
neighCellConfig: The MBSFN subframe allocations of all neighbour cells are identical to or subsets of that in the serving cell (2)
t-ReselectionEUTRA: 2s
sib5
interFreqCarrierFreqList: 3 items
Item 0
InterFreqCarrierFreqInfo
dl-CarrierFreq: 1401
q-RxLevMin: -118dBm (-59)
t-ReselectionEUTRA: 2s
threshX-High: 4dB (2)
threshX-Low: 10dB (5)
allowedMeasBandwidth: mbw50 (3)
.... ...1 presenceAntennaPort1: True
cellReselectionPriority: 6
neighCellConfig: The MBSFN subframe allocations of all neighbour cells are identical to or subsets of that in the serving cell (2)
Item 1
InterFreqCarrierFreqInfo
dl-CarrierFreq: 6375
q-RxLevMin: -118dBm (-59)
t-ReselectionEUTRA: 2s
threshX-High: 6dB (3)
threshX-Low: 10dB (5)
allowedMeasBandwidth: mbw75 (4)
..1. .... presenceAntennaPort1: True
cellReselectionPriority: 6
neighCellConfig: The MBSFN subframe allocations of all neighbour cells are identical to or subsets of that in the serving cell (2)
Item 2
InterFreqCarrierFreqInfo
dl-CarrierFreq: 3075
q-RxLevMin: -118dBm (-59)
t-ReselectionEUTRA: 2s
threshX-High: 4dB (2)
threshX-Low: 10dB (5)
allowedMeasBandwidth: mbw25 (2)
.... .1.. presenceAntennaPort1: True
cellReselectionPriority: 5
neighCellConfig: The MBSFN subframe allocations of all neighbour cells are identical to or subsets of that in the serving cell (2)
There is another 4G Band 3 network available - Telesol. Telesol has 1.5x more Band 3, but MTN has other bands too.
MTN's Band 3 4G coverage is not widely available yet.