TCP is the only protocol widely available for reliable end-to-end congestion-controlled network communication, and thus it is the one used for almost all communications. Unfortunately, TCP is not designed with high-performance networking and computing. Thus the research for TCP to obtain good throughput in high-performance networking and computing is in progress all over the world actively. In this paper, we propose a new scheme which makes a TCP system achieve high throughput even with small buffer. The receive buffer almost empties due to the characteristic of original TCP but the amount of physical memory assigned for the buffer cannot be reduced because TCP flow control will downgrade TCP performance with the reduced buffer. However a TCP system applying our proposed scheme can reduce the size of physically assigned receive buffer without downgrading TCP performance. And then we use PID control mechanism as a tool to adjust the size of VRB properly. Lastly, we compare the throughput with two schemes, proposed scheme and original TCP scheme. As a result, the TCP using VRB obtains 46% higher throughput than the original one. And we also compare the amount of memory necessary for achieving the maximum throughput between two schemes. The result of second comparison shows that the proposed TCP spends 43% less memory than the tuned original TCP for same throughput.