ID3D11DeviceContext:::CopyResource is bottleneck in my particle system

Question

I have a snow particle system and I use simplex noise for creating turbulence effect. At first, I made calculations on the CPU, and the simplex noise calls obviously were the bottleneck. The MAX_NUM_PARTICLES limit was 50k (to hold the 60 fps). There was a fatal drop for 75-100k.

That's why I moved the calculation to compute shader like here.

Snow particle system is working, however, I got a weird result: the fps limit left the same, but it does not fall so critically -- I can render 100-200k with 45 fps.

At first, I played with Dispatch params, but the fps was the same for 512, 1, 1 and 1, 1, 1 calls. Second, I convinced that simplex noise calculations were not a problem just passing input coordinates into the output buffer.

Then I commented out different parts of the code and realized that ID3D11DeviceContext:::CopyResource is the bottleneck. I use RWStructuredBuffer buffer to gain compute shader results and, as I know, it requires additional buffer with D3D11_USAGE_STAGING usage and D3D11_CPU_ACCESS_READ flag. So think I can't refuse to use it.

Please share your ideas What can I do about it?

Code part:

    // Create a system memory version of the buffer to read the results back from.
    outputDesc.Usage = D3D11_USAGE_STAGING;
    outputDesc.BindFlags = 0;
    outputDesc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;

    result = (device->CreateBuffer(&outputDesc, 0, &mRWOutputBuffer));
    if (FAILED(result))
        return false;

    D3D11_UNORDERED_ACCESS_VIEW_DESC uavDesc;
    uavDesc.Buffer.FirstElement = 0;
    uavDesc.Buffer.Flags = 0;
    uavDesc.Buffer.NumElements = m_pParticleSystem->GetInstaceCount();
    uavDesc.Format = DXGI_FORMAT_UNKNOWN;
    uavDesc.ViewDimension = D3D11_UAV_DIMENSION_BUFFER;

    result = device->CreateUnorderedAccessView(mRWBuffer, &uavDesc, &mRWUAV);
    if (FAILED(result))
        return false;

    m_pParticleSystem->FillConstantDataBuffer(deviceContext, mInputBuffer);

    // Enable Compute Shader
    deviceContext->CSSetShader(mComputeShader, nullptr, 0);

    deviceContext->CSSetShaderResources(0, 1, &mInputView);
    deviceContext->CSSetUnorderedAccessViews(0, 1, &mRWUAV, 0);


    // Dispatch
    deviceContext->Dispatch(512, 1, 1);

    // Unbind the input textures from the CS for good housekeeping
    ID3D11ShaderResourceView* nullSRV[] = { NULL };
    deviceContext->CSSetShaderResources(0, 1, nullSRV);

    // Unbind output from compute shader ( we are going to use this output as an input in the next pass, 
    // and a resource cannot be both an output and input at the same time
    ID3D11UnorderedAccessView* nullUAV[] = { NULL };
    deviceContext->CSSetUnorderedAccessViews(0, 1, nullUAV, 0);

    // Disable Compute Shader
    deviceContext->CSSetShader(nullptr, nullptr, 0);


    // Copy result **(FPS DROP HERE)**
    deviceContext->CopyResource(mRWOutputBuffer, mRWBuffer);

Thank you for your answer in advance.