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    <p><code>r1</code> is more efficient. The <code>InputStreamReader</code> itself doesn't have a large buffer. The <code>BufferedReader</code> can be set to have a larger buffer than <code>InputStreamReader</code>. The <code>InputStreamReader</code> in <code>r2</code> would act as a bottleneck. </p> <p>In a nut: you should read the data through a funnel, not through a bottle.</p> <hr> <p><strong>Update</strong>: here's a little benchmark program, just copy'n'paste'n'run it. You don't need to prepare files.</p> <pre><code>package com.stackoverflow.q3459127; import java.io.BufferedInputStream; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.File; import java.io.FileInputStream; import java.io.FileWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.Reader; public class Test { public static void main(String... args) throws Exception { // Init. int bufferSize = 10240; // 10KB. int fileSize = 100 * 1024 * 1024; // 100MB. File file = new File("/temp.txt"); // Create file (it's also a good JVM warmup). System.out.print("Creating file .. "); BufferedWriter writer = null; try { writer = new BufferedWriter(new FileWriter(file)); for (int i = 0; i &lt; fileSize; i++) { writer.write("0"); } System.out.printf("finished, file size: %d MB.%n", file.length() / 1024 / 1024); } finally { if (writer != null) try { writer.close(); } catch (IOException ignore) {} } // Read through funnel. System.out.print("Reading through funnel .. "); Reader r1 = null; try { r1 = new BufferedReader(new InputStreamReader(new FileInputStream(file), "UTF-8"), bufferSize); long st = System.nanoTime(); for (int data; (data = r1.read()) &gt; -1;); long et = System.nanoTime(); System.out.printf("finished in %d ms.%n", (et - st) / 1000000); } finally { if (r1 != null) try { r1.close(); } catch (IOException ignore) {} } // Read through bottle. System.out.print("Reading through bottle .. "); Reader r2 = null; try { r2 = new InputStreamReader(new BufferedInputStream(new FileInputStream(file), bufferSize), "UTF-8"); long st = System.nanoTime(); for (int data; (data = r2.read()) &gt; -1;); long et = System.nanoTime(); System.out.printf("finished in %d ms.%n", (et - st) / 1000000); } finally { if (r2 != null) try { r2.close(); } catch (IOException ignore) {} } // Cleanup. if (!file.delete()) System.err.printf("Oops, failed to delete %s. Cleanup yourself.%n", file.getAbsolutePath()); } } </code></pre> <p>Results at my Latitude E5500 with a <a href="http://www.seagate.com/docs/pdf/datasheet/disc/ds_momentus_7200_3.pdf" rel="noreferrer">Seagate Momentus 7200.3</a> harddisk:</p> <pre> Creating file .. finished, file size: 99 MB. Reading through funnel .. finished in 1593 ms. Reading through bottle .. finished in 7760 ms. </pre>
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    1. POShould I buffer the InputStream or the InputStreamReader?
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    1. COIf the underlying InputStream was a FileInputStream, would the two Readers perform differing amounts of disk reads throughout an entire read process?
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    2. COI checked it using perfmon, I don't see noticeable differences. I'll update the answer soon to include a benchmark code snippet.
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